Drilling-fluid control-monitoring apparatus

ABSTRACT

A control-monitoring apparatus, which is adapted to cooperate in a drilling-fluid circulation system, having a level indicating apparatus to sense the level change of the drilling-fluid in the fluid-pits and to provide an output level-signal in response thereto; a pump transducer is connected to each pump, each pump transducer being connected to a flow register which provides an indication of the total volume of drilling-fluid being moved through a pump; and a return-flow indicator to provide an output return flow-signal indicative of the flow of drilling-fluid through the return flow line. The control-monitoring apparatus being constructed to provide the necessary drilling-fluid parameters during the drilling operation when the drilling-fluid is being circulated through the borehole, and during the initial filling of the borehole with drilling-fluid prior to the beginning of the drilling operation.

Unite States Patent McKean et al. [45] Apr. W, 1973 DRILLING-FLUIDCONTROL- MONITORING APPARATUS Primary Examiner-Jerry W. Myracle [75]Inventors: George W. McKean; Hugh H. Ben- Anomey Dunlap Laney Hessm &Dougherty son, both of Oklahoma City, Okla.

57 TRACT [73] Assignee: Oklahoma A control-monitoring apparatus, whichis adapted to clty Oklacooperate in a drilling-fluid circulation system,having 22 Filed; 17 1970 a level indicating apparatus to sense the levelchange of the drilling-fluid m the fluid-pits and to provide an PP99,136 output level-signal in response thereto; a pump transducer isconnected to each pump, each pump trans- 52 us. Cl ..73/1ss, 175/48dPcer i register Y 511 int. Cl. ..E21b 47/04 "l mdlcam the mime f [58]Field of Search ..73/155 432 HA bemg hmugh a pump; and a 175/38 166/256dicator to provide an output return flow-signal indicative of the flowof drilling-fluid through the return flow line. The control-monitoringapparatus being [56] References cued constructed to provide thenecessary drilling-fluid P 2 aramaters the drllllng Operation when thedrilling-fluid is being circulated through the borehole, 2,290,4087/1942 Crites ..73/ 155 and during the initial filling of the boreholewith 3,608,653 9/1971 Rehm-m drilling-fluid prior to the beginning ofthe drilling Knauth 0 station 2,5l6,452 7/1950 Giers et al. p

227,576 /1880 Read ..73/229 X 33 Claims, 8 Drawing Figures 58 55 52 /252 /2 52 1 52 .60 o PUMP PUMP 5 Q,- fi J 2;- pen E TEAL/500662 54 1 4 22t 44 l M 40 42 M /7 70 44 ya PEN/EM FLan/ WAWDUCEE 62 34 55%; rufi cee55 4 ll m b l I e 55 /az a0 I30 FLOW mum/w 7') 56 J EEq/s'rE-e 46704 702,/a4 72 l F/esr zecoeaee FLOW sE-cauo Z a i 82 0211/5 PEG/57E? lame/2mae/vz- 74 a M I 4 I08 M 1/0 PM? l 92 5222'? ,0 7' lusm/mm-wsCOA/f/A/UUUS "/usumA/Ews CONTINUOUS LEI/EL P/T lA/D/CATDE PIT AVG/C4701?FLOW IUD/547772 FMW IAN/14702 wow/v02 HIGH-LOW PI? /96 HIGH-LOW FLOW 4/5ACTUAI'OE H5 ACTH/77G? 96 122 L L L D I xoo l F02 /l /2q PATENTEU APR 1@1973 3,726,136

SHEET 3 OF 4 mww w k g. mum 5 U \%m m w M W m Qh v 5 p w W a m T H I Aan gw/ A W W Q a u w. y 1 QRJ v \m 1 A H G, fi wmkfiwmw wmfi mkumw r \sm Roi 5 QR W/ Q QM w 4 a 3w g. g QR MN 3 Nu QM $1 3 ma 5% mm mmDRILLING-FLUID CONTROL-MONITORING APPARATUS BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates generally toimprovements in control-monitoring apparatus and, more particularly, butnot by way of limitation, to a control-monitoring apparatus to indicatedrilling-fluid parameters.

2. Description of the Prior Art During various drilling operations, asparticularly related to the drilling of an oil or a gas well, a drillingfluid is commonly circulated and partially retained in the borehole forvarious reasons, as for example; to keep the gas pressure substantiallysealed in the borehole, and to remove the drill-bit shavings from theborehole. During the startup of the drilling operations and during thedrilling operations per se, it is important that the operator haveavailable certain information relating to the flow of the drilling-fluidso that the operator will be in a position to quickly and intelligentlymake certain operational or procedural decisions relating to thedrilling operation. For example, the amount of drilling-fluid initiallypumped into the borehole, the level of the drilling-fluid in thefluid-pits, and the amount or, more particularly, the relative amount ofthe drilling-fluid being returned to the fluidpits, constitute some ofthe drilling-fluid parameters needed by the operator.

The above-mentioned drilling-fluid parameters provide an indication tothe operator of certain possible problems which may exist at varioustimes during the drilling operation. For example: an increasingly highlevel of drilling-fluid in the fluid-pits may indicate a possibleblow-out, and thereby provide a basis for an operators decision toincrease the weight of the drilling-fluid being circulated into theborehole; a decreasingly low level of drilling-fluid may indicate apossible loss of drilling-fluid in a formation cavity, a conditioncommonly referred to in the art as loss-circulation; and a knowledge ofthe relative flow of drilling-fluid in the return flow line generallyindicates to the operator such conditions as, for example, that theborehole has been filled with a sufficient amount of drilling-fluid tobegin the drilling operations.

Various solutions have been attempted in the past to provide an operatorwith at least some of the drillingfluid parameters or data mentionedabove. However, as the drilling operations have become more complex andsophisticated, it has become increasingly important that the operatorhave available, in an immediate and useable form, the maximumdrilling-fluid data which includes sufficient drilling-fluid parametersupon which the various operational decisions can be quickly andefficiently based. Due particularly to the size and complexity of themodern drilling-rigs and to the increasingly large number of auxiliarycomponents being supported or utilized in cooperation with suchdrilling-rigs, it has also become important that certain drilling-fluidparameters be made available at various remote, rig-locations or atvarious remote control positions.

SUMMARY OF THE INVENTION An object of the invention is to provide acontrolmonitoring apparatus to indicate drilling-fluid parmeters.

Another object of the invention is to provide a control-monitoringapparatus to indicate the level of drilling-fluid in the fluid-pits.

A further object of the invention is to provide a control-monitoringapparatus to indicate the total change of drilling-fluid level in thefluid-pits.

A still further object of the invention is to provide acontrol-monitoring apparatus to indicate the volume of drilling-fluidrequired to initially fill the borehole.

Another object of the invention is to provide a control-monitoringapparatus to indicate the flow of drilling-fluid in a return flow linefrom the borehole to the fluid-pits.

One other object of the invention is to provide a control-monitoringapparatus to provide the drilling-fluid parameters in a quick, efficientand immediately useable form.

Another object of the invention is to provide a control-monitoringapparatus to indicate a preset high and a preset low level ofdrilling-fluid in the fluid-pits.

A still further object of the invention is to provide acontrol-monitoring apparatus to indicate a preset high and a preset lowflow of the drilling-fluid through the return flow line.

A yet further object of the invention is to provide a control-monitoringapparatus having a remote, drillingfluid parameter indicator.

One other object of the invention is to provide a moisture-proof shaftseal.

A still further object of the invention is to provide acontrol-monitoring apparatus to indicate drilling-fluid parameters whichis economical in construction and operation.

Other objects and advantages of the invention will be evident from thefollowing detailed description when read in conjunction with theaccompanying drawings which illustrate one embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a schematic, diagrammaticalview of a control-monitoring apparatus constructed in accordance withthe present invention.

FIG. 2 is a partial sectional, partial diagrammatical view of a returnflow indicator utilized in the controlmonitoring apparatus of FIG. 1 toindicate the flow of drilling-fluid in the return flow pipeline. I

FIG. 3 is a view of one end of the stationary member of themoisture-seal of FIG. 2, looking toward the return flow transducerhousing.

FIG. 4 is a schematic view of a level indicating apparatus utilized inthe control-monitoring apparatus of FIG. 1 to indicate the level of thedrilling-fluid in the fluid-pits.

FIG. 5 is a schematic view showing the electrical interconnectionbetween some of the control components of the control-monitoringapparatus of FIG. 1.

FIG. 6 is an elevational view showing some of the control components ofthe control-monitoring apparatus of FIG. 1.

FIG. 7 is a side elevational view showing some of the control componentsof the control-monitoring apparatus of FIG. 1.

FIG. 8 is a partial sectional, partial diagrammatical view showing theremote drilling-fluid indicator of the control-monitoring apparatus ofFIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings ingeneral and to FIG. I in particular, shown therein and designated by thegeneral reference numeral IQ is a control-monitoring apparatus adaptedto cooperate in a drilling-fluid circulation system to provide aninstantaneous and a continuous indication of various drilling-fluidparameters, in a manner to be described in more detail below. Theconstruction and operation of the control-monitoring apparatus willinitially be described with respect to the general overall operationthereof, as diagrammatically shown in FIG. 1, and the construction andoperation of the preferred embodiment of the various control componentswill then be described in greater detail below.

The drilling-fluid circulation system, diagrammatically shown in FIG. 1,includes a plurality of fluid-pits 12, each fluid-pit I2 being sized tostoringly retain a predetermined volume of drilling-fluid, and beinginterconnected by pipelines 14. Although three fluid-pits 12 are shownin FIG. I, it is well known in the art that the exact number offluid-pits l2 utilized in a particular drilling operation will depend tosome extent upon the quantity of drilling-fluid utilized and theeconomical size of each particular fluid-pit 12.

A pair of pumps 16 and 17 are connected in parallel by a pair of flowpipelines I8 and 20, and the suction side of each pump I6 and I7 isconnected to one of the fluid-pits 12 via a flow pipeline 22. Thedischarge side of each pump 16 and 17 is connected to a flow pipeline 24via a pair of flow pipelines 26 and 28. The flow pipeline 24 isconnected to a borehole, diagrammati cally shown in FIG. l anddesignated therein by the general reference 30.

The pump I6 is driven by a pump drive 32 and the pump 17 is driven by apump drive 34 as diagrammatically shown in FIG. I. The pumps 16 and 1'7and the pump drives 32 and 34 are sized and connected to move or pumpsome of the drilling-fluid from the fluidpit 12 in fluidic communicationtherewith via the flow pipeline 22 into a portion of the borehole 30 viathe flow pipeline 24, during one portion of the overall drillingoperation. Some of the drilling-fluid is returned from the borehole 30to the fluid-pits 112 via a return flow pipeline 36, during certainportions of the overall drilling operation, as will be made moreapparent below.

Although only two pumps I6 and I7 are shown in FIG. 1, it will beapparent from the foregoing to those skilled in the art that additionalpumps may be utilized or, in another form, only one of the pumps I6 or17 may be utilized in a particular drilling-fluid circulation system.The sizing, the interconnection and the various control valves used incooperation with the pumps 16 and 17 are well known in the art and adetailed description thereof is not required herein.

As shown in FIG. 1, a level indicating apparatus 38 is connected to eachfluid-pit 12. Each level indicating apparatus 38 is constructed andadapted to sense the level of the drilling-fluid in one of thefluid-pits l2, and to provide an output level-signal indicative of thedrilling-fluid level thus sensed. More particularly, each levelindicating apparatus 38 is connected in series via a pair of conduits 40and 42 to provide a common output via a pair of conduits 4d and 46. Eachlevel indicating apparatus 38 is thus interconnected such that theoutput conduits 44 and 36 provide a total output levelsignal 48, whichis indicative of the drilling-fluid level in the fluid-pits 112.

Each level indicating apparatus 38, as shown in FIG. 1, includes a floatStl disposed in the drilling-fluid in one of the fluid-pits I2, and atransducer 52. Each transducer 52 is connected to one of the floats 50,and is adapted to cooperate therewith to translate the mechanicalmovement of the interconnected float 50 into an appropriate outputsignal to provide the output level-signal 48, in a manner to bedescribed in greater detail below.

It should be particularly noted that specific embodiments of the controlcomponents of the control-monitoring apparatus 10 may be mechanically,electrically, pneumatically, hydraulically or fluidically operated and,therefore, the term signal as used above and below, refers moregenerally to a control output produced by either type of controlcomponent. A preferred embodiment of some of the control components willbe described in greater detail below and, in those instances, theparticular control signal will be more specifically identified.

As diagrammatically shown in FIG. 1, a return flow indicator 56 isdisposed in a portion of the return flow pipeline 36. The return flowindicator 56 is constructed and adapted to responsively indicate therelative flow of the drilling-fluid through the return flow pipeline,and to provide an output return flow-signal indicative of the sensedflow of drilling-fluid, in a manner as to be described in greater detailbelow.

More particularly, the return flow indicator 56 includes, a paddle 58which is disposed in a portion of the return flow pipeline 36, and areturn flow transducer 60 which is connected to the paddle 58. Thereturn flow transducer 6% is constructed and adapted to translate themechanical movement of the paddle 58 into an output return flow-signal62 which is indicative of the flow of drilling-fluid through the returnflow pipeline 36.

The control-monitoring apparatus 10 also includes a pair of pumptransducers 64 and 66. As shown in FIG. I, the pump transducer 64 isconnected to the pump 16 and is adapted to cooperate therewith toprovide an output flow-signal 741) indicative of the volume ofdrilling-fluid being moved through the pump 16. The pump transducer asis connected to the pump 17, and is adapted to cooperate therewith toprovide an output flow-signal '72 which is indicative of the volume ofdrilling-fluid being moved through the pump 17.

The control-monitoring apparatus 10 includes a drilling-fluid indicationapparatus, diagrammatically shown in FIG. I and designated therein bythe general reference numeral 74}. The drilling-fluid indicationapparatus 74 is adapted to cooperate with the other components of thecontrol-monitoring apparatus 10 and, more particularly, to providevarious output indication signals, each indication signal beingindicative of a particular drilling-fluid parameter, in a manner to bedescribed in detail below.

The drilling-fluid indication apparatus 74 includes: a first recorder 76which is constructed and adapted to provide output indication signalsindicative of the drilling-fluid level in the fluid-pits l2, and asecond recorder '78 which is constructed and adapted to provide outputindication signals indicative of the flow of the drilling-fluid in thereturn flow pipeline 36, and a flow register apparatus 80 which isconstructed and adapted to provide an output indication signal,indicative of the volume of drilling-fluid being moved through the pumps16 and 17. In a preferred form, the drillingfluid indication apparatus74 is contained in a single control cabinet and disposed generally nearthe drilling operations, in a position where the various outputindications are readily observable by the operator, for reasons whichwill become more apparent below.

As shown in FIG. 1, the first recorder 76 includes, a first recorderdrive 82 which is adapted to receive the output level-signal 48 from thelevel indicating apparatus 38, and to provide an output drive-signal 84in response to the output level-signal 48. The output drive-signal 84 ofthe first recorder drive 82 is connected to a pit indicating apparatus86 and, more particularly, to the input of an instantaneous pitindicator 90 and to the input of a continuous pit indicator 92.

The instantaneous pit indicator 90 is constructed and adapted to receivethe output drive-signal 84 of the first recorder drive 82, and toprovide an output level indi cation-signal 94 which is indicative of thedrilling-fluid level in the fluid-pits 12 at a particular instant oftime. The continuous pit indicator 92 is, more particularly, adapted toreceive the output drive-signal 84 of the first recorder drive 82, andto provide an output level indication-signal 96 which is indicative ofthe drilling fluidlevel in the fluid-pits 12 over a predetermined periodof time.

The output drive-signal 84 of the first recorder drive 82 is alsoconnected to the input of a high-low pit actuator 98, as shown inFIG. 1. The high-low pit actuator 98 is constructed and adapted toreceive the output drive-signal 84, and to provide an output high-signal100 when the output drive-signal 84 reaches a preset high level, and toprovide an output low-signal 102 when the output drive-signal 84 reachesa preset low level. The high-low pit actuator 98 is thus adapted toindicate a predetermined high and a predetermined low drilling-fluidlevel-change in the fluid-pits 12 via the output high-signal 100 and theoutput low-signal 102.

As shown in FIG. 1, the second recorder 78 includes a second recorderdrive 106 which is adapted to receive the output return flow-signal 62from the return flow transducer 60, and to provide an output drivesignal108 in response to the return flow-signal 62. The output drive-signal108 of the second recorder drive 106 is connected to the input of areturn flow indicating apparatus 110 and, more particularly, to theinput of an instantaneous flow indicator 112 and to the input of acontinuous flow indicator 1 14.

The instantaneous flow indicator 112 is constructed and adapted toreceive the output drive-signal 108 of the second recorder drive 106 andto provide an output flow indication-signal 116 which is indicative ofthe flow of drilling-fluid in the return flow pipeline 36 at aparticular instant of time. The continuous flow indicator 114 is, moreparticularly, adapted to receive the output drive-signal 108 of thesecond recorder drive 106, and to provide an output flowindication-signal 118 .which is indicative of the flow of drilling-fluidthrough the return flow pipeline 36 over a predetermined period of time.

The output drive-signal 108 of the second recorder drive 106 is alsoconnected to the input of a high-low flow actuator 120, as shown inFIG. 1. The high-low flow actuator 120 is constructed and adapted toreceive the output drive-signal 108, and to provide an outputhigh-signal 122 when the output drive-signal 108 reaches a preset highlevel, and to provide an output low-signal 124 when the outputdrive-signal 108 reaches a preset low level.

The high-low flow actuator 120 is thus adapted to indicate apredetermined high and a predetermined low level of drilling-fluid flowin the return flow pipeline 36 via the output high-signal 122 and theoutput low-signal 124.

The flow register apparatus 80 of the drilling-fluid control indicationapparatus 74 includes a continuity actuator which is constructed andadapted to receive the output flow-signals 70 and 72 from the pumptransducers 64 and 66. The continuity actuator 130 has an actuatedposition and a deactuated position and is, more particularly,constructed to provide continuity between the pump transducer 64 and aflow register 132, and to provide continuity between the pump transducer66 and a flow register 134 in an actuated position of the continuityactuator 130. As indicated in FIG. 1, in an actuated position of thecontinuity actuator 130, the output flow-signal 70 is connected to theinput of the flow register 132 and the output flow-signal 72 isconnected to the input of the flow register 134.

The continuity actuator 130 is constructed such that the continuityactuator 130 will remain in the actuated position until the borehole 30has been sufficiently filled with drilling-fluid. The continuityactuator 130 is then deactuated automatically so that the flow registers132 and 134 indicate only the drilling-fluid required to initially fillthe borehole 30, for reasons to be made more apparent below.

The flow register 132 is constructed and adapted to receive the outputflow-signal 70 and to provide an output volume indication signal 136,indicative of the volume of drilling-fluid being moved through the pump16. The flow register 134 is constructed and adapted to receive theoutput flow signal 72 and to provide an output volume indication signal138, indicative of the volume of drilling-fluid being moved through thepump 17.

A power supply is connected to the drilling-fluid control indicationapparatus 74, to provide the operating power for the various controlcomponents therein, as shown in FIG. 1.

The control-monitoring apparatus 10 also includes, a remote pit levelindicator 142, as shown in F16. 1. The output drive-signal 84 from thefirst recorder drive 82 is connected to the remote pit level indicator142, and the remote pit level indicator 142 is constructed and adaptedto receive the drive-signal 84 and to provide an output level indicationsignal, indicative of the drillingfluid level in the fluid-pits 12, at aremote position with respect to the drilling-fluid indication apparatus74.

Operation of FIG. 1

The control-monitoring apparatus 10, as generally described above,provides an instantaneous indication of the level of the drilling-fluidin the fluid-pits 12 via an output level indication-signal 94, andsimultaneously provides a continuous indication of the drillingfluidlevel of the fluid-pits 12 via the output level indication-signal 96. Apreset or predetermined high and low drilling-fluid level in thefluid-pits 12 is indicated via the output high-signal 100 and the outputlow-signal 102, respectively.

The control-monitoring apparatus also provides an instantaneousindication of the flow of drilling-fluid in the return flow pipeline 36via an output flow indication-signal 1 16, and simultaneously provides acontinuous indication of the drilling-fluid flow in the return flowpipeline 36 via the output flow indication-signal 118. A preset orpredetermined high and low drillingfluid flow in the return flowpipeline 36 is indicated via the output high signal 122 and the outputlow-signal 124.

In addition to the above described drilling-fluid parameters, thecontrol-monitoring apparatus 10 also provides an indication of thevolume of drilling-fluid being moved to the borehole 30 via the pumps 16and 17 via the flow indication signals 136 and 138.

It should be particularly noted that the output signals 94, 100, 102,96, 116, 122, 124, 118, 136 and 138 of the drilling-fluid indicationapparatus 74 are perceivable by the operator, as will be made moreapparent below, and provide the operator with the necessarydrilling-fluid parameter data required at the various stages of theoverall drilling operation. In some instances, the signals, mentionedabove, may provide a visual or an audible indication or, in certaininstances, both a visual and an audible indication are provided. Apreferred embodiment of the various control component apparatus and theparticular signal produced thereby will be described in greater detailbelow.

During the drilling operation, either the pump 16 or 17, or both pumps16 and 17 are pumping a predetermined volume of drilling-fluid from thefluid-pits 12 into the borehole 30.

The drilling-fluid is then recirculated back to the fluid-pits 12 viathe return flow pipeline 36.

The first recorder 76 and the second recorder 78 are operating tocontrollingly monitor the drilling-fluid level in the fluid-pits l2 andflow of drilling-fluid through the return flow pipeline 36. Thecontinuity actuator 130 is deactuated, thereby interrupting continuitybetween the pump transducers 64 and 66 and the flow registers 132 and134. Depending upon such factors as, for example, the size of the rigand the location of the drilling-fluid indication apparatus 74, theoperator may also have the remote pit level indicator 142 operablyconnected to the first recorder drive 82, thereby providing anindication of the level of drillingfluid in the fluid-pits 12 at aremote location.

When it becomes necessary to stop the drilling operation, for example,to change a drill-bit, the level of the drilling-fluid will be, for themost part, lowered in the borehole 30 as the drilling pipe is removedfrom the borehole 30. Thus, to maintain head pressure on the formationsdown the hole, it is necessary to fill the borehole 30 with thedrilling-fluid.

During the filling of the borehole 30, the drillingfluid parametersindicating the volume of drilling-fluid that was required to fill theborehole 30, and an indication that the borehole 30 is filled withdrilling-fluid are required. The continuity actuator 130 is moved orpositioned in the actuated position, thereby establishing continuitybetween the pump transducers 64 and 66 and the flow registers 132 and134, respectively. The output flow indication-signal 116 of theinstantaneous flow indicator 112 will indicate a zero or a no flow ofdrilling-fluid through the return flow pipeline 36 via the output flowindication-signal 1 16.

In this position of the drilling-fluid indication apparatus 10, the pumpdrives 32 and 34 are started, and the pumps 16 and 17 will begin to fillthe borehole 30 with drilling-fluid from the fluid-pits 12. The pumptransducer 64 and the flow register 132 are connected via the continuityactuator 130, and the output volume indication-signal 136 of the flowregister 132 indicates the volume of drilling-fluid being pumped throughthe pump 16. The pump transducer 66 and the flow register 134 areconnected via the continuity actuator 130, and the output volumeindication-signal 138 of the flow register 134 indicates the volume ofdrilling-fluid being pumped through the pump 17.

In a preferred form, the pumps 16 and 17 are, more particularly,reciprocating pumps, having a known volume of fluid pumpedper stroke. Inthis instance, the pump transducers 64 and 66 are constructed to countthe number of strokes of the pump 16 or 17 respectively, and the outputsignals and 72, more particularly, indicate the number of strokes of thepump 16 or 17. The flow registers 132 and 134 register the total numberof strokes of the pump 16 or 17, respectively, during the period of timethe continuity actuator is in an actuated position. In one form, forexample, the pump transducers 64 and 66 are constructed to close aswitch at the end of each pump stroke, and the pump register 132 and 134thus provides an output numerical indication of the total number of pumpstrokes via the output signals 136 and 138. Pump transducers andregisters of the type generally described above are well known in theart and a detailed description of construction and operation thereof isnot required herein.

When the borehole 30 is filled with drilling-fluid, the continuityactuator 130 is deactuated, thereby interrupting the continuity betweenthe pump trlnsducers 64 and 66 and the flow registers 132 and 134,respectively. The output volume indication signals 136 and 138 thusindicate to the operator the total volume of drilling-fluid required tofill the borehole 30.

In a preferred form, the instantaneous flow indicator 112 and, moreparticularly, the output flow indicationsignal 1 16 therefrom, is adial-indicator. In this embodiment, which will be described in greaterdetail below, a switch is interposed in the continuity actuator 130, theswitch being in the open position when the dial-indicator indicates azero or no flow of drilling-fluid in the return flow pipeline 36. Whenthe dial-indicator is moved 011' of the zero position by thedrive-signal 108, thereby indicating a flow of drilling-fluid in thereturn flow pipeline 130, the switch is closed. in the closed positionof the switch, the continuity actuator 130 is deactuated.

After the borehole 30 has been initially filled with drilling-fluid, thedrilling operations can again be resumed. The control-monitoringapparatus 10 and particularly the drilling-fluid parameter indicationapparatus 74 being specifically adapted to provide the necessarydrilling-fluid parameters during the drilling operation when thedrilling-fluid is being circulated through the borehole 30 and duringthe period when the borehole 30 is being initially filled with thedrillingfluid.

Embodiment of FIGS. 2 and 3 Shown in FIGS. 2 and 3 is a preferredembodiment of a return flow indicator 56 to be utilized in thecontrolmonitoring apparatus 10, generally described above. As shown inFIG. 2, the return flow indicator 56 includes: a paddle 58, havingopposite end portions 200 and 202, which is disposed in a lower portionof the return flow pipeline 36 (shown in dashed-lines in FIG. 2), suchthat a portion thereof is in contact with a portion of thedrilling-fluid flowing through the return flow line 36. Thus, anydrilling-fluid which is flowing in the return flow pipeline 36 willcontact a portion of the paddle 58, thereby moving the paddle 58 in amanner to be described in more detail below.

The paddle 58, generally near the end 200 thereof, is secured to apaddle shaft 204 by an interconnecting flange 206, as shown in FIG. 2.The paddle shaft 204 has opposite end portions 208 and 210, and is sizedsuch that a portion thereof rotatingly extends through a shaft aperture212 in a return flow transducer housing 214. The return flow transducerhousing 214, as shown in FIG. 2 is constructed to rotatingly receive aportion of the paddle shaft 204, and to provide a moistureproofcontainer for the paddle shaft 204 bearing supports (not shown) and thereturn flow transducer 60, both of which are disposed and supported in aportion of the return flow transducer housing 214.

As indicated in FIG. 2, the paddle shaft 204, generally adjacent the end210 thereof, is connected to the return flow transducer 60. The returnflow transducer 60 is constructed and adapted to translate themechanical, rotational movement of the paddle shaft 204 and to providethe output return flow-signal 62 proportional thereto.

From the foregoing, it will be apparent to those skilled in the art thatdrilling-fluid flowing through the return flow pipeline 36 will causethe paddle 58 to move, generally in the direction of the drilling-fluidflow, about the interconnection of the paddle 58 and the paddle shaft204, and the movement of the paddle 58 will thereby cause an incrementalrotational movement of the paddle shaft 204. Thus the rotation of thepaddle shaft 204 and consequently the output return flow-signal 62 isproportional or indicative of the relative flow of drilling-fluidthrough the return flow pipeline 36, rather than being a volumetricindication. Transducers adapted to receive rotational shaft movementsand to translate such a mechanical movement into an output signalporportional thereto, such as described above with respect to the returnflow transducer 60, are well known in the art and a detailed descriptionof the construction and operation thereof is not required herein.

A moisture-seal 214 is connected to the return flow transducer housing214 and to the paddle shaft 204. The moisture-seal 214 is constructedand adapted to provide a substantially moisture-tight seal between thepaddle shaft 204 and the return flow transducer housing 214, in a mannerto be made more apparent below.

The moisture-seal 214 includes a hollow stationary member 216 having anouter periphery 218. The stationary member 216 is sealingly secured onone end thereof to the return flow transducer housing 214 generallyabout the shaft aperture 212, as shown in FIG. 2. The stationary member216 is sized and positioned to encompass the shaft aperture 212 and toencompass a portion of the paddle shaft 204, such that the paddle shaft204 is freely rotatable in the hollow portion of the stationary member216.

As shown in FIGS. 2 and 3, a lip portion 220 is formed on the end of thestationary member 216, opposite the end thereof which is secured to thereturn flow transducer housing 214. The lip portion 220 extends adistance generally radially from the stationary member 216 about theentire outer periphery 218 thereof.

The moisture-seal 214 also includes a hollow rotating member 222, havingan inner periphery 224 and an outer periphery 226. As shown more clearlyin FIG. 2, one end of the rotating member 222 is secured to a portion ofthe paddle shaft 204 via a flange portion 228 which extends radiallyabout the outer periphery 226 of the rotating member 222. The rotatingmember 222 and particularly the inner periphery 224 thereof is sized toextend a distance axially over the uppermost end portion of the lip 220of the stationary member 216, as shown in FIG. 2, thereby leaving aclearance between the rotating member 222 and the outer periphery of thelip portion 220 of the stationary member 216, for reasons which will bemade apparent below.

Operation of FIGS. 2 and 3 The return flow indicator 56 senses therelative flow of drilling-fluid in the return flow pipeline 36 andprovides the output return flow-signal 62, proportional thereto. Moreparticularly, the output return flowsignal 62 is proportional to theincremental rotation of the paddle shaft 204 resulting from thedrilling-fluid in the return flow pipeline 36 contacting the paddle 58.

The moisture-seal 214 is constructed to cooperate with the rotatingpaddle shaft 204 and a portion of the return flow transducer housing 214to prevent moisture from entering the return flow transducer housing 214via the shaft aperture 212, thereby damaging the various operating andcontrol components therein. Since the rotating member 222 is securedabout the paddle shaft 204, as shown in FIG. 2, moisture is preventedfrom entering the transducer housing 214 along the paddle shaft 204 viathe interconnection between the rotating member 222 and the paddle shaft204. Further, since the stationary member 216 is secured about the outerperiphery 218 thereof to the return flow transducer housing 214,moisture is prevented from entering the return flow transducer housing214 via the connection between the stationary member 216 and the returnflow transducer housing 214.

The lip 220 of the stationary member 216 cooperates with the overhangingportion of the rotating member 222 to prevent moisture from enteringinto the hollow portion, generally defined by the inner periphery 224,of the rotating member 222. Thus, moisture is directed onto the outerperiphery 218 of the stationary member 216 and discharged from the lowerportion thereof. In other words, moisture is guided by the overhangingportion of the rotating member 222 and the lip 220 generally about theouter periphery 218 of the stationary member 216 and thus the moistureis prevented from contacting the portion of the paddle shaft 204disposed in the hollow portions of the rotating member 222 or thestationary member 216.

The moisture-seal 214 thus prevents moisture from entering the returnflow transducer housing 214 along the paddle shaft 204. Since themoisture-seal 214 has no contacting or wearing components, themoistureproofing of the return flow transducer housing 214 is providedin a manner requiring less field maintenance, and in a manner assuringan operable, moisture-proof seal over a relatively long period ofoperating time.

Embodiment of FIG. 4

Shown in FIG. 4 is a preferred embodiment of a portion of the levelindicating apparatus 38 to be utilized in the control-monitoringapparatus 10, described generally before. As shown in FIG. 4, each levelindicating apparatus 38 comprises a variable resistor apparatus 302,which includes a resistor 304 and a positionable contacting arm 306.

In this embodiment of the level indicating apparatus 38, as shown inFIG. 4, each contact arm 306 is connected to one of the floats 50, insuch a manner that as the float 50 is moved from a preset position bychanges in the drilling-fluid level in the fluid-pits 12, the mechanicalmovement of the float 50 alters the contacting position between theinterconnected contact arm 306 and the cooperating resistor 304. Asindicated in FIG. 4, the resistors 304 are connected in series, and thusthe total electrical resistance in the conduits 44 and 46 iscontrollingly varied in response to changes in the drilling-fluid levelin the fluid-pits 12.

The level indicating apparatus, as shown in FIG. 4, also includes, acalibrating resistor 310, having a manually adjustable contact arm 312cooperating with a resistor 314, in a manner similar to that describedbefore with respect to the contacting arm 306 and the resistors 304. Thecalibrating variable resistor 310 is interposed in the conduit 44 sothat the pit indicating apparatus may be initially calibrated to apreset point or, more particularly, so that the total resistance in theconduits 44 and 46 may be initially calibrated to a preset level at thecommencement of the drilling operations.

Each variable resistor apparatus 302 and the calibrating variableresistor apparatus 310 are con nected to the first recorder drive 82, asindicated in FIGS. 1 and 4, and thus the output drive-signal 84 of thefirst recorder drive 82 will vary in response to the total change ofresistance in the conduits 44 and 46 or, in other words, to the outputlevel indication signal 48. In a preferred form, the first recorderdrive 82 is an electric motor, and the output level indication signal 48would, in that instance, be connected in the motor control circuit suchthat the electric motor is drivingly operated in response to a change ofresistance in the conduits 44 and 46 or, in other words, in response tothe output level indication signal 48.

It will be apparent from the foregoing to those skilled in the art, thatthe output level-signal 48 is more particularly indicative of a totallevel-change in the volume of drilling-fluid retained in the fluid-pits12. Thus the output level-signal 48 is indicative of a change ofdrilling-fluid volume, rather than being indicative of a total drillingfluid volume per se.

Operation of FIG. 4

Each level indicating apparatus 38, as described above, cooperates toprovide the output level-signal 48, which is indicative of the totaldrilling-fluid, levelchange in the fluid-pits 12. After each fluid-pit12 has been initially filled with a predetermined volume ofdrilling-fluid, the output level-signal 48 is adjustingly set to apredetermined position via the calibrating variable resistor apparatus310.

The output drive-signal 84 of the first recorder 76 is thus responsiveto the total change of drilling-fluid level in the fluid-pits 12. It hasbeen found that the total change of drilling-fluid level in thefluid-pits 12 is more indicative of certain conditions in the overalldrilling operation, and does constitute an important drilling fluidparameter to be considered by the operator.

Embodiment of FIG. 5

Shown in detail in FIG. 5, is a preferred embodiment of the electricalinterconnection between the pump transducers 64 and 66 and the flowregisters 132 and 134; and the electrical interconnection between thehigh-low pit actuator 98 and the high-low flow actuator 120 and therespective output indicating apparatus cooperating with each high-lowactuator 98 and 120 to provide an output high or an output low visualand audible indication.

As shown in FIG. 5, and for reasons which will become more apparentbelow, the high-low flow actuator 120 is schematically shown as a pairof normally opened switches 400 and 402, the switch 400 being referredto below as the low-switch 400 and the switch 402 being referred tobelow as the high-switch 402. The high-low pit actuator 98 is alsoschematically shown in FIG. 5 as a pair of normally opened switches 404and 406, the switch 404 being referred to below as the low-switch 404and the switch 406 being referred to below as the high-switch 406.

The high-low flow actuator 120 is constructed such that when the outputdrive-signal 108 of the second recorder drive 106 reaches a preset highor a preset low level, the low-switch 400 or the high-switch 402,respectively, is closed, thereby indicating a low or a high level ofdrilling-fluid flow through the return flow pipeline 36. The high-lowpit actuator 98 is constructed such that when the output drive-signal 84of the first recorder drive 82 reaches a preset high or a preset lowlevel, the low-switch 404, or the high-switch 406, respectively, isclosed, thereby indicating a low or a high level-change ofdrilling-fluid in the fluid-pits 12.

The pump transducers 64 and 66 are schematically shown in FIG. 5, as anormally opened switch 408 and 410, respectively. The pump transducers64 and 66 are, more particularly, adapted to cooperate with areciprocating pump, as mentioned before, and in this instance, the totalnumber of times the switch 408 or 410 is closed during a particularoperating cycle of the control-monitoring apparatus 10 will beindicative of the volume of fluid being moved from the fluid-pits 12 tothe borehole 30 via the pumps 16 or 17, respectively.

As shown in FIG. 5, the operating power is provided by the power supply140 via a pair of power conductors 412 and 414. A main power switch 416is interposed in the power conductor 412, and in the opened position ofthe power switch 416, as shown in FIG. 5, the power supply 140 isdisconnected from the various control components shown in FIG. 5. Anoverload fuse 418 is interposed in the power conductor 414, and the fuse418 is adapted to protect the control components from an excessive oroverload current, in a manner well known in the art.

As shown in FIG. 5, it has been assumed that the power supply 140 is ofthe alternating current type, and further, that various controlcomponents are operated or require a direct current type of powersupplyjThe power supply 140 is therefore coupled to the variousoperating components via a transformer 430, and a rectifying circuithaving a pair of diodes 422 and 424 connected in parallel and a filtercapacitor 426. The diodes 422 and 424 and the filter capacitor 426cooperate to provide a DC power source via the control power conductors428 and 430 to the various control components, in a manner well known inthe art and requiring no further detailed description herein.

As shown in FIG. 5, a low pit indicator lamp 432 is connected on oneside thereof to the control power conductor 428 and on the opposite sidethereof to the low-switch 404 of the high-low pit actuator 98 via aconductor 434. A high pit indicator lamp 436 is connected on one sidethereof to the control power conductor 428 and on the opposite sidethereof to the highswitch 406 of the high-low pit actuator 98 via aconductor 438. The pit indicator lamps 432 and 436 are adatped andconnected to provide a visual output indication when the low-switch 404or the high-switch 406 is closed, in a manner to be described more fullybelow.

As shown in FIG. 5, a low flow indicator lamp 440 is connected on oneside thereof to the control power conductor 428 and on the opposite sidethereof to the low-switch 400 of the high-low flow actuator 120 via aconductor 442. A high flow indicator lamp 444 is connected on one sidethereof to the control power conductor 428 and on the opposite sidethereof to the highswitch 402 of the high-low flow actuator 120 via aconductor 446. The flow indicator lamps 440 and 444 are adapted andconnected to provide a visual output indication when the low-switch 400or the high-switch 402 is closed, in a manner to be described in moredetail below.

The side of the indicator lamp 432 which is connected to the low-switch404 is also connected to one side of a transistor oscillator 447 via aconductor 450. The side of the indicator lamp 436 which is connected tothe high-switch 406, is also connected to the oscillator 447 via aconductor 452 which, as shown in FIG. 5, is connected to the conductor450.

As shown in FIG. 5, a normally-opened, double-pole, single-throw switch454 is interposed in the conductors 452 and 450 generally between theindicator lamps 432 and 436, respectively, and the oscillator 447. Moreparticularly, one set of contacts of the switch 454 is interposed in theconductor 452 and the other set of contacts of the switch 454 isinterposed in the conductor 450.

The side of the indicator lamp 440 which is connected to the low-switch400 is connected to the conductor 450 via a conductor 455. The side ofthe indicator lamp 444 which is connected to the high-switch 402 isconnected to the conductor 450 via a conductor 456. Thus, the conductors455 and 456 are each connected to one side of the oscillator 447 via theconductor 450.

As shown in FIG. 5, a normally-opened, double-pole, single-throw switch458 is interposed in the conductors 455 and 456 generally between theindicator lamps 440 and 444, respectively, and the oscillator 447. Moreparticularly, one set of contacts of the switch 458 is interposed in theconductor 455 and the other set of contacts of the switch 458 isinterposed in the conductor 456.

The oscillator 447, as shown in FIG. 5, is also connected to the controlpower conductor 428, and to a speaker 448. The oscillator 447 isconstructed to establish a tone by oscillating at a predeterminedfrequency when the oscillator 447 is connected to the control powerconductors 428 and 430. The speaker 448 is constructed to receive thetone produced by the oscillator 447 and to provide an audible indicationin the closed position of either the low-switch 400, the high-switch402, the low-switch 404 or the high-switch 406. A diode 459 isinterposed in each conductor 450, 452, 455 and 456, generally betweenthe switches 454 and 458 and the oscillator 447, as shown in FIG. 5.

As shown in FIG. 5, one contact of each switch 400 and 402 of thehigh-low flow actuator is connected to the control power conductor 430via a conductor 460. Also, one of the contacts of each switch 404 and406 of the high-low pit actuator 98 is connected to the control powerconductor 430 via a conductor 462.

From the foregoing and from FIG. 5, it will be apparent to those skilledin the art, that in the opened position of the switches 400, 402, 404and 406, electrical continuity between the control power conductors 428and 430 and the indicator lamps 432, 436, 440 and 444 is interrupted,and the indicator lamps 432, 436, 440 and 444 are thus de-energized. Italso follows from the foregoing, that when the double-pole, single-throwswitches 454 and 458 are in the opened position, as shown in FIG. 5,electrical continuity between the control power conductors 428 and 430and oscillator 447 is thereby interrupted, and thus the oscillator 447is in the de-energized position. However, it should also be noted that,even in the closed position of the switches 454 and 458, the electricalcontinuity between the oscillator 447 and the control power conductors428 and 430 is interrupted when the switches 400, 402, 404 and 406 arein the opened position, for reasons which will be-made more apparentbelow.

The continuity actuator 130, as shown in FIG. 5, includes a pair ofmomentary, push-button actuators 464 and 466. The momentary actuator 464has a set of cooperating open contacts 468 and, as indicated in FIG. 5,the momentary actuator 464 is constructed such that in the closedposition thereof, the momentary actuator 464 bridges the cooperatingcontacts 468, thereby establishing electrical continuity thereacross.The momentary actuator 466 has a set of cooperating open contacts 470and, as indicated in FIG. 5, the momentary actuator 466 is constructedsuch that in the closed position thereof, the momentary actuator 466bridges the cooperating contacts 470, thereby establishing electricalcontinuity thereacross associated therewith.

The continuity actuator 130 also includes a holding coil relay 472,having a relay coil 474, a set of cooperating contacts 476 and 478 and arelay switch arm 480. The holding coil relay 472 is shown in FIG. in thede-energized position thereof and, in that position, the relay switcharm 480 is in contacting engagement with the relay contact 478, therebyestablishing electrical continuity therebetween.

The continuity actuator 130 also includes a relay 482 and a relay 484.The relays 482 and 484 are connected to the switches 408 and 410 of thepump transducers 64 and 66, respectively and adapted to cooperate withthe holding coil relay 472 to establish electrical continuity betweenthe switch 408 and the flow register 132 and between the switch 410 andthe flow register 134, in one position of the relays 472, 482 and 484,as will be described in greater detail below.

The relay 482 includes, a relay coil 486 and a double set of cooperatingcontacts, one set of contacts being designated in FIG. 5 by thereference numerals 488 and 490, and the other set of contacts beingdesignated in FIG. 5 by the reference numerals 492 and 494. A relayswitch arm 496 cooperates with the relay contacts 488 and 490, and arelay switch arm 498 cooperates with the relay contacts 492 and 494. Asshown in FIG. 5, the relay switch arms 496 and 498 are in thede-energized position of the relay 482 and, in that position, the relayswitch arm 496 is in contacting engagement with the relay contact 490,and the relay switch arm 498 is in contacting engagement with the relaycontact 494.

The relay 484 includes, a relay coil 500 and a double set of cooperatingcontacts, one set of contacts being designated in FIG. 5 by thereference numerals 502 and 504, and the other set of contacts beingdesignated in FIG. 5 by the reference numerals 506 and 508. A relayswitch arm 510 cooperates with the relay contacts 502 and S04, and arelay switch arm 512 cooperates with the relay contacts 506 and 508. Asshown in FIG. 5, the relay switch'arms 510 and 512 are in thede-energized position of the relay 484 and, in that position, the relayswitch arm 510 is in contacting engagement with the contact 504, and therelay switch arm 512 is in contacting engagement with the relay contact508.

The control circuitry, as shown in FIG. 5, also includes a fill-drilltoggle switch 513 and a zero-flow switch 514, both of which are shown inFIG. 5 in the opened position thereof. A flow indicator lamp 515 is alsoconnected in the continuity actuator 130, in a manner and for reasonswhich will be described in greater detail below.

As shown in FIG. 5, the power conductor 430 is connected to one side ofthe switch 408 via a conductor 516, to one side of the switch 410 via aconductor 518, and to one side of the switch 514 via a conductor 520.The opposite side of the switch 408 is connected to the relay switch arm498 via a conductor 522; the opposite side of the switch 410 isconnected to the relay switch arm 512 via a conductor 524; and theopposite side of the switch 514 is connected to one side of thefill-drill switch 513 via a conductor 526.

The control power conductor 428 is connected to the flow register 134via a pair of interconnected conductors 528 and 530. The flow register134 is connected to the flow register 132 via a conductor 532 which isalso connected to the conductor 528.

As shown in FIG. 5, the flow register 132 is connected to the relaycontact 492 via a conductor 534, and the flow register 134 is connectedto the relay contact 506 via a conductor 536.

The momentary actuator 464 and, more particularly, one of the contacts468 thereof, is connected to the control power conductor 430 via aconductor 540 and a conductor 542. The other contact 468 of themomentary actuator 464 is connected to the relay contact 502 and to oneside of the coil 500 of the relay 484 via a conductor 544.

The momentary actuator 466 and, more particularly, one of the contacts470 thereof, is connected to the control power conductor 430 via aconductor 546 which is connected to the conductor 540. The other contact470 of the momentary actuator 466 is connected to the relay contact 488and to one side of the coil 486 of the relay 482 via a conductor 548.

The side of the coil 486, opposite the side thereof connected to theconductor 548, is connected to the relay contact 478 of the holding coilrelay 472 by a conductor 550. As shown in FIG. 5, the side of the coil500, opposite the side thereof connected to the conductor 544, isconnected to the relay contact 478 of the holding coil relay 472 via aconductor 552 which is connected to the conductor 550.

The control power conductor 430 is connected to the relay switch arm 496by a conductor 554 and a conductor 556, the conductor 556 beingconnected to the conductor 540. The control power conductor 430 is alsoconnected to the relay switch arrn 510 via a conductor 558 which isconnected to the conductors 554 and 556. One side of the coil 474 of theholding coil relay 472 is connected to the flow indicator lamp 515 via aconductor 560, as shown in FIG. 5. The opposite side of the coil 474 isconnected to the control power conductor 428 via a conductor 564 whichis connected to the conductor 530 and the conductor 528, and connectedto the relay switch arm 480 via a conductor 566.

As shown in FIG. 5, a flow switch 580 is interposed in the conductor460, generally between the high-low flow actuator and the connectionbetween the conductors 430 and 460. The flow switch 580 is shown in FIG.5 in the opened position thereof, and is adapted and positioned toprovide an audible indication of drilling-fluid flow in the return flowpipeline 36, in a manner to be described in more detail below.

Operation of FIG. 5

The various control components are shown in FIG. 5 in the de-energizedposition, that is the position of the particular control component in adeactuated status or a status wherein power is not being suppliedthereto via the control power conductors 428 and 430. When the mainpower switch 416 is moved to the closed position, operating power isprovided to the control power conductors 428 and 430. In this initialposition, the indicator lamps 432, 436, 440 and 444 are not lit, sincethe switches 400, 402, 404 and 406 are in the opened position, therebyinterrupting the electrical continuity between the control powerconductors 428 and 430 and the indicator lamps 432, 436, 440 and 444.

When a low drilling-fluid level-change is sensed by the highblow pitindicator 98, the low-switch 404 will be closed, thereby establishingelectrical continuity between the control power conductors 428 and 430and the low pit indicator lamp 432. The energizing or lighting of theindicator lamp 432 thus provides a perceptible, visual indication ofhigh level-change of drilling-fluid in the fluid-pits 12. In the closedposition of the low-switch 404, the oscillator 447 will not be energizedor, in other words, will not produce an audible signal, since the switch454 is in the opened position, thereby interrupting electricalcontinuity between the oscillator 447 and the control power conductors428 and 430.

The closing of the high-switch 406 will energize or light the high-pitindicator lamp 436; the closing of the low-switch 400 will energize orlight the low indicator lamp 440; and the closing of the high-switch 402will energize or light the high indicator lamp 444, each indicator lamp436, 440 and 444 being energized in a manner similar to that describedin detail above with respect to the closing of the low-switch 404 andthe energizing or lighting of the low indicator lamp 432. Neither theclosing of the low-switch 400, the highswitch 402, nor the high-switch406 will energize the oscillator 447 to produce an audible signal viathe speaker 448, since the switches 454 and 458 are in the openedposition.

It is apparent from the foregoing, that if the switch 454 is moved tothe closed position, the closing of the low-switch 404 or the closing ofthe high-switch 406 will not only energize or light the low indicatorlamp 432 or the high indicator lamp 436, respectively, but the closingof either switch 404 or 406 will also establish electrical continuitybetween the oscillator 447 and the control power conductors 428 and 430,thereby producing an audible signal via the speaker 448 indicating arelatively low or high change in the drilling-fluid level in thefluid-pits 12. After the switch 458 has been moved to the closedposition, the closing of either the low-switch 400 or the high-switch402 of the high-low flow indicator 120 will not only produce a visualindication of a relatively low or relatively high flow in the returnflow pipeline 36, but the closing of either the low-switch 400 or thehigh-switch 402 will also establish electrical continuity between theoscillator 447 and the control power conductors 428 and 430, therebyproducing an audible indication of a low or a high flow ofdrilling-fluid in the return flow pipeline 36, in a maner similar tothat described before with respect to the low-switch 404, thehigh-switch 406 and the switch 454. From the foregoing, it is apparentthat the audible indication signal produced from the speaker 448 iscontrollable by the operator either closing the switches 454 or 458, orleaving the switches 454 or 458 in the respective opened positionthereof.

Before refilling the borehole 30 with drilling-fluid, the operator willestablish electrical continuity between the pump transducers 64 and 66and the flow registers 132 or 134, respectively, by actuating thecontinuity actuator 130. Since, during this portion or cycle of theoverall drilling operation no drilling-fluid will be flowing through thereturn flow pipeline 36, the zeroor noflow switch 514 will be in theopen position. In a preferred form, as mentioned before, the no-flowswitch 514 is actuated open by a dial-indicator which is positioned onthe drilling-fluid indication apparatus 74 to indicate a zero flow ofdrilling-fluid. The fill-drill switch 513 is then moved to the closedposition. Since the zero-flow switch 514 is in the open position, therelay 472 will remain in the de-energized position, as shown in FIG. 5.

In this position, electrical continuity between the flow register 132and the pump transducer 64 is initially established by the depressing ormoving of the momentary actuator 466 to the actuated position or, inother words, to a position wherein the momentary actuator 466 bridgesthe cooperating open contacts 470 thereof. The bridging of the opencontacts 470 provides electrical continuity between the relay coil 486of the relay 482 and the control power conductors 428 and 430 via theconductors 540, 546, 548, 550, 566, 564 and 528, thereby energizing therelay 482. In the energized position of the relay 482, the relay switcharm 496 will be moved into contacting engagement with the relay contact488, and the relay switch arm 498 will be moved into contactingengagement with the relay contact 492. The moving of the relay switcharm 496 into contacting engagement with the relay contacts 488cooperates with the holding coil relay 47 2 to maintain the relay 482 inthe energized position after the momentary actuator 466 has beenreleased, thereby opening the contacts 470 thereof.

In the energized position of the relay 482, the pump transducer 64 is inelectrical continuity with the flow register 132 and the control powerconductors 428 and 430. As mentioned before, the pump transducer 64 isconstructed such that the number of times that the switch 408 is closedduring a certain operating cycle is indicative of the volume ofdrilling-fluid flowing through the pump 16. From FIG. 5, it is apparentthat when the switch 408 is in the closed position, the pump transducer64 and the flow register 132 are in electrical continuity with thecontrol power conductors 428 and 430, and the flow register 132 isadapted to register or indicate that the switch 408 or, moreparticularly, the number of times the switch 408 is in the closedposition during a certain period of time.

If the pump 17 is also to be utilized to move or pump drilling-fluidinto the borehole 30, it will be necessary to establish electricalcontinuity between the flow register 134 and the pump transducer 66 sothat the flow of drilling-fluid through the pump 17 will also beregistered. To establish such electrical continuity, the momentaryactuator 464 is actuated or, in other words, moved to a position whereinthe momentary actuator 464 bridges the cooperating open contacts 468thereof. The bridging of the open contacts 468 provides electricalcontinuity between the relay coil 500 of the relay 484 and the controlpower conductors 428 and 430 via the conductors 540, 542, 544, 552, 550,566, 564 and 528, thereby energizing the relay 484. In the energizedposition of the relay 484, the relay switch arm 510 will be moved intocontacting engagement with the relay contact 502, and the relay switcharm 512 will be moved into contacting engagement with the relay contact506. The moving of the relay switch arm 510 into contacting engagementwith the relay contacts 502 cooperates with the holding coil relay 472to maintain the relay 484 in the energized position after the momentaryactuator 464 has been released, thereby opening the cooperating contacts468. In the energized position of the relay 484, the pump transducer 66is in electrical continuity with the flow register 134 and the controlpower conductors 428 and 430. Thus, when the switch 410 is in the closedposition, the pump transducer 66 and the flow register 134 are inelectrical continuity with the control power conductors 428 and 430, andthe flow register 134 registers or indicates the total number of timesthe switch 410 is moved to the closed position during a certainoperating period of time, in a manner similar to that described withrespect to the switch 408 of the pump transducer 64.

When the drilling-fluid begins to flow through the return flow pipeline36, the zero-flow switch 514 will be moved to the closed position,thereby establishing electrical continuity between the flow indicatorlamp 515 and the control power conductors 428 and 430. The flowindicator lamp 515 is thus energized, and provides a visual indicationthat the drilling-fluid has begun to flow in the return flow pipeline.

The closing of the zero flow switch 514 also establishes the electricalcontinuity between the coil 474 and the control power conductors 428 and430. The closing of the zero-flow switch 514, thus energizes the coil474 of the holding coil relay 472, thereby moving the relay switch arm480 therein to the energized position or, in other words, moving therelay switch arm 480 into contacting engagement with the open contact476 of the holding coil relay 472.

The moving of the relay switch arm 480 to the energized position, incontacting engagement with the open contact 476, interrupts electricalcontinuity between the coils 486 and 500 of the relays 482 and 484,respectively. Thus, when the holding coil relay 472 is energized by theclosing of the zero-flow switch 514, the relays 482 and 484 will bede-energized, thereby interrupting electrical continuity between thepump transducers 64 and 66 and the flow registers 132 or 134,respectively.

During the filling of the borehole 30 with drillingfluid, as describedabove, if the operator also desires an audible indication thatdrilling-fluid has begun to flow in the return flow pipeline 36, theoperator will initially close the switch 458. In other words, the switch458 is closed prior to establishing electrical continuity between thepump transducers 64 and 66 and the flow registers 132 and 134,respectively, or at the beginning of the refilling operation. In apreferred form, the flow switch 580 is actuated open by a dial-indicatorwhich is positioned on the drilling-fluid indication apparatus 74, in amanner similar to that described before with respect to the no-flowswitch 514. Since there is no flow of drilling-fluid in the return flowpipeline 36 during the initial stages of the refilling operation, theflow switch 580 will be in the open position, and the lowswitch 400 ofthe high-low flow actuator 120 will be in the closed position. When thedrilling-fluid begins to flow through the return flow pipeline 36, theflow switch 580 will be closed, thereby establishing electricalcontinuity between control power conductors 428 and 430 and theoscillator 447 through the low-switch 400. In this position, theoscillator 447 will be energized, and an audible indication of thedrilling-fluid flow in the return flow pipeline 36 will be provided viathe speaker 448. The speaker 448 will continue to provide the audibleindication until the flow in the return flow pipeline 36 is sufficientto deactuate or open the low-switch 400 of the high-low flow indicator120, thereby interrupting the electrical continuity between the controlpower conductors 428 and 430 and the oscillator 447, or until theoperator opens the switch 458.

It is apparent from the foregoing, that the output signals and 102 ofthe high-low pit actuator 98, more particularly, refer to the visualindication provided by the pit indicator lamps 432 and 436 and, in someinstances, to the audible signal provided by the speaker 448. By thesame token, the output signals 122 and 124 of the high-low flow actuator120, more particularly, refer to the visual indication provided by theflow indicator lamps 440 and 444 and, in some instances, to the audiblesignal provided by the speaker 448.

Embodiment of FIGS. 6 and 7 Shown in FIGS. 6 and 7 is a preferredembodiment of a high-low actuator 98 or 120, a recorder drive apparatus82 or 106, an instantaneous indicator 90 or 112, and acontinuous'indicator 92 or 114, all of which are constructed andconnected to be utilized in the control-monitoring apparatus 10 of FIG.1, and more particularly in the drilling-fluid indication apparatus 74.The various control components shown in FIGS. 6 and 7 are constructedsuch that they can be utilized in either the first recorder 76 or thesecond recorder 78, as will be made more apparent below.

Referring more particularly to FIG. 6, the highJow actuator 98 or issupported in the first recorder 76 or the second recorder 78,respectively, and is constructed and adapted to support the low-switch400 or 404 and the high-switch 402 or 406 in an adjustingly, actuatingposition. The low-switch 400 or 404 is disposed on and secured to acarrier 600, having a pair of apertures 602 and 604 (shown indashed-lines) extending therethrough. The aperture 604 is threaded, andthe aperture 602 is sized to slidingly receive an elongated screw, in amanner and for reasons to be made more apparent below.

The high-switch 402 or 406 is disposed on and secured to a carrier 606,having a pair of apertures 608 and 610 (shown in dashed-lines) extendingtherethrough. The aperture 608 is threaded, and the aperture 610 issized to slidingly receive an elongated screw, in a manner and forreasons to be made more apparent below.

A pair of elongated screws 612 and 614 are rotatingly supported in aportion of the recorder 76 or 78 by a pair of brackets 616 and 618. Aguide shaft 620 is also supported by the brackets 616 and 618, the guideshaft 620 being sized to slidingly extend through a support aperture 622formed through a central portion of each carrier 600 and 606, only theaperture 622 in the carrier 600 being shown in FIG. 6. The guide shaft620, more particularly, provides guiding support for the carriers 600and 606, during the adjustment of the high-low actuator 98 or 120, in amanner to be described in greater detail below.

As indicated in FIG. 6, the screw 612 is sized to slidingly extendthrough the sliding aperture 602 of the carrier 600 and to threadinglyextend through the aperture 608 of the carrier 606. The aperture 602 inthe carrier 600 is, more particularly, sized to have a larger diameterthan the screw 612, for reasons to be made more apparent below.

The screw 614 is sized to extend through the aperture 604 of the carrier600 and to slidingly extend through the aperture 610 of the carrier 606.The aperture 610 of the carrier 606 has a larger diameter than the screw614, for reasons to be described in more detail below.

The high-low actuator 98 or 120 also includes a low adjusting knob 624and a high adjusting knob 626. The low adjusting knob 624 is gearinglyconnected (not shown) to the elongated screw 614 in such a manner thatby turning the low adjusting knob 624, the screw 614 is rotated. Thehigh adjusting knob 626 is gearingly connected (not shown) to the screw612 such that by turning the high adjusting knob 626, the screw 612 isturned or rotated.

Since the carrier 600 and, more particularly, the aperture 604 therein,threadingly engages the screw 614, and further, since the guide rod 620supports the carrier 600 in a non-engaging relationship with the screw612, when the screw 614 is turned by turning the low knob 624, thecarrier 600 will be moved toward the support 616 or the support 618,depending upon the direction of rotation of the low knob 624, therebyadjusting the high actuating position of the low-switch 400 or 404, aswill be made more apparent below. From the foregoing, it will beapparent that when the screw 612 is turned by turning the high knob 626,the carrier 600 will be moved toward the support 616 or the support 618,depending upon the direction of rotation of the high knob 626, therebyadjusting the low actuating position of the switch 402 or 406, as willbe made more apparent below.

The low-switch 400 or 404 and the high-switch 402 or 406 are supportedin the recorder 76 or 78 to cooperate with a control cam 630, thecontrol cam 630 being shaped and positioned to actuate or close thelow-switch 400 or 404 or the high-switch 402 or 406, in one positionthereof. The control cam 630 has opposite end portions 632 and 634, anda low cam surface 636 and a high cam surface 638 formed on a portionthereof, as shown clearly in FIG. 6. As shown in FIGS. 6 and 7, thecontrol cam 630 is pivotally secured in the recorder 76 or 78 via a camshaft 640, which is pivotally secured to the control cam 630 generallynear the end 632 thereof.

As shown in FIGS. 6 and 7, the continuous indicator 92 or 114 includes,a recorder arm 642 having a marking end 644 formed on one end portionthereof. The control cam 630 is securedly connected to a portion of theend of the recorder arm 642, opposite the marking end 634 thereof,generally near the end 632 of the control cam 630. The marking end 644of the recorder arm 642 is adapted to continuously and permanently marka portion of a chart 646, in such a manner that the mark made therebyprovides a record of a particular drillingfluid parameter over apredetermined period of time. As indicated in FIGS. 6 and 7, the chart646 is disposed generally between the control cam 630 and the markingend 644 of the recorder arm 642. The utilization of a circular chart andmarker adapted to provide a continuous mark upon such a chart is wellknown in the art, and a detailed description of the contruction andoperation thereof is not necessary herein.

As shown in FIGS. 6 and 7, the end 634 of the control cam 630 isgearingly connected to a shaft 650 via a gear 652. The gear- 652 issecured to the shaft 650, and the shaft 650 is rotatingly supported inthe recorder 76 or 78.

As shown more clearly in FIG. 7, the recorder drive 82 or 106 is, in apreferred form, an electric motor having an output shaft 654. The outputshaft 654 of the motor is gearingly connected to the shaft 650 via agear 656 and a gear 658. The gear 656 is secured to the shaft 654, andthe gear 658 is secured to the shaft 650.

It is apparent from the foregoing, that the rotational movement of theshaft 654 is gearingly transmitted to the shaft 650 via the gears 656and 658, and further that the rotation of the shaft 650 is gearinglytransmitted to the control cam 630 via the gear 652 and the geared end634 of the control cam 630.

As shown more clearly in FIG. 7, the shaft 650 extends through a support660, and a dial-indicator 662 is secured to the end of the shaft 650.The dial-indicator 662 will thus be rotated, following the rotation ofthe shaft 650, for reasons to be made more apparent below.

Operation of FIGS. 6 and 7 The recorder drive 82 or 106, as shown moreclearly in FIG. 7, is adapted to receive the level-signal 48 or theflow-signal 62, and to drivingly rotate the shaft 654 an incrementaldegree of rotation in response thereto. The rotation of the shaft 654 isgearingly transmitted to the shaft 650, and thus the dial-indicator 662and the control cam 630 are moved an incremental amount in response tothe rotational movement of the shaft 654. More particularly, thedial-indicator 662 is moved through a certain degree of rotationfollowing the rotational movement of the shaft 650 and the control cam630 is moved through a certain degree of rotation about the pivot shaft640 in response to the rotation of the shaft 650.

The dial-indicator 662 cooperates with reference numerals provided onthe recorder 76 or 78 to provide a visual and instantaneous indicationof the total level change in the drilling-fluid level in the fluid-pits12, or to indicate the flow of drilling-fluid in the return flowpipeline 36, depending upon whether the apparatus shown in FIGS. 6 and 7is utilized in the first recorder 76 or the second recorder 78. The useof a dial-indicator to provide an instantaneous indication of aparticular parameter is well known in the art, and a detaileddescription of the recorder case and the placement of the numeralsthereabout to cooperate with the rotational movement of thedial-indicator 662 is not required herein.

Since the recorder arm 642 is securedly affixed to a portion of thecontrol cam 630, the position of the marking end 644 with respect to thechart 646 will be controllably positioned by the incremental movement ofthe control cam 630. Thus, the rotation of the shaft 650 willcontrollingly position the marking end 644 on the chart 646 via thegearing interconnection between the shaft 650 and the recorder arm 642provided by the gear 652 and the control cam 630. The recorder arm 642and, more particularly, the marking end 644 thereof, thus cooperates toprovide a continuous indication of either the total level change ofdrilling-fluid in the fluid-pits 12, or the drilling-fluid flow in thereturn flow pipeline 36 over a predetermined period of time, dependingupon whether the apparatus is utilized in the first recorder 76 or thesecond recorder 78.

The low-switch 400 or 404 and the high-switch 402 or 406 are positionedon the high-low actuator 98 or 120, such that in the normal operatingposition of the control-monitoring apparatus 10, the control cam 630 isnot in engagement with either the low-switch 400 or 404, nor thehigh-switch 402 or 406. When the signal to the recorder drive 82 or 106reaches a predetermined high level, the incremental degree of rotationtransmitted to the control cam 630 will cause the control cam 630 torotate to a position wherein the low cam surface 636 actuatinglycontacts the low-switch 400 or 404, thereby closing the low-switch 400or 404. When the control signal to the recorder drive 82 or 106 reachesa predetermined low level, the recorder drive 82 or 106 will cause thecontrol cam 630 to be rotated to a position wherein the high cam surface638 actuatingly engages the high-switch 402 or 406 thereby closing thehigh-switch 402 or 406.

It is apparent from the foregoing, that by changing the position of thecarrier 600 or the carrier 606 on the high-low actuator 98 or 120, thedegree of rotation required to bring the cam surfaces 636 or 638 into anactuating engagement with the low-switch 400 or 404 or the high-switch402 or 406 is controllably altered thereby. Thus, by turning the controlknobs 624 or 626, the operator can alter the actuating low level or theactuating high level of the high-low actuator 98 or 120.

In a preferred form, the various control components, shown in FIGS. 6and 7, are utilized in both the first recorder 76 and the secondrecorder 78. In this embodiment of the invention, it is also apparentfrom the foregoing that the output drive-signal 84 or 108 of the firstrecorder drive 82 or the second recorder drive 106 refers, moreparticularly, to the incremental degree of rotation of the shaft 654 inresponse to the particular input control signal. The outputindication-signal 94 or 116 of the instantaneous indicator 90 or 112refers, more particularly, to the position of the dial-indicator 662,and the output indications-signals 96 and 118 of the continuousindicator 92 or 114 refers, more particularly, to the marking of thechart 646 by the marking end 644.

Embodiment of FIG. 8

A preferred embodiment of a remote pit level indicator 142, and thecooperating components of the first recorder 76 are shown in detail inFIG. 8. It should be particularly noted, that all of the components ofthe first recorder 76 are not shown in FIG. 8, but rather only thosecomponents necessary to describe the operation of the remote pit levelindicator 142.

As shown in FIG. 8, a first servo-control motor 700 having a servo shaft702 is supported in the first recorder 76. The servo shaft 702 isgearingly connected to the recorder shaft 650 via a pair of bevel gears704 and 706. The gear 704 is, more particularly, secured to the servoshaft 702, and the gear 706 is, more particularly, secured to therecorder shaft 650.

The servo-control motor 700 is connected to a second servo-control motor708, which is supported in the remote return flow indicator 142. Thesecond servo-control motor 708 has an output servo shaft 710, which isgearingly connected to a shaft 712 via a pair of bevel gears 714 and716. The bevel gear 716 is secured to the shaft 712, the bevel gear 714being secured to the servo shaft 710.

The first servo-control motor 700 and the second servo-control motor 708are interconnected such that the rotational output of the servo shaft710 is directly proportional or, as referred to in the art, slavinglyfollows the rotation of the servo shaft 702 of the first servo-controlmotor 700. The servo-control motors 700 and 708 are, in a preferredform, synchro-control motors, and the interconnection between twoservocontrol motors, in a manner as indicated above with respect to thefirst servo-control motor 700 and the second servo-control motor 708, iswell known in the art and a detailed description of the interconnectiontherebetween and the operation thereof is not required herein.

The shaft 712 is rotatingly supported in the remote pit level indicator142, as shown in FIG. 8. One end of the shaft 712 is in biasingengagement with a biasing spring 720, which is disposed in a retainer722 secured to a portion of the remote pit level indicator 142. As shownin FIG. 8, one end portion of the shaft 712 is also supported in aportion of the retainer 722. The biasing spring 720 is sized to bias theshaft 712 in a general direction 724, as indicated in FIG. 8. The bevelgears 714 and 716 are disposed and the bias spring 720 is sized suchthat, in an operating position of the remote return flow indicator 142,the biasing spring 720 biases the shaft 712 in the direction 724 to aposition wherein the bevel gears 714 and 716 are in gearing engagement.

A knob 726 is secured on one end of the shaft 712 opposite the endthereof in biasing engagement with the spring 720. The knob 7 26 isdisposed on the remote return flow indicator 142 such that an operatorcan move the knob in a general direction 728 thereby moving the shaft712 against the biasing force of the spring 720. The knob 726 and theshaft 712 are further positioned and disposed such that the shaft 712can be moved a sufficient distance in the direction 728 to disengage thegearing interconnection between the bevel gears 714 and 716, for reasonsto be made apparent below.

A dial-indicator 730 is secured to the shaft 712, generally near theknob 726 end thereof. The dial 730 thus provides a visual outputindication response to the rotation of the shaft 712.

It should be noted, that in a preferred form, the bevel gears 702 and706, and the bevel gears 714 and 716 are cooperatingly sized such thatthe incremental degree of rotation of the shaft 650 is amplified, thusresulting in a proportionally greater degree of rotation of the shaft712 in the remote return flow indicator 142. In this manner, a smallindication of drilling-fluid level in the fluid-pits 12 will produce agreater degree of rotation of the dial-indicator 730 of the remote pitlevel indicator 142, and thus be more readily perceptible at a greaterdistance by an operator.

Operation of FIG. 8

The remote pit level indicator 142, as described above, is particularlyadapted to provide a visual indication of a particular parameter at aremote position with respect to the main recorder, or more particularly,the first recorder 76. The output drive signal 84 of the first recorderdrive 82, or more particularly, the incremental rotation of the shaft654 of the first recorder drive 82, gearingly drives the shaft 702 ofthe first servo-control motor 700. Since the second servo-control motor708 is connected to the first servo-control motor 700 in such a mannerthat the rotational movement shaft 710 of the second servo-control motor708 slavingly follows the rotational movement of the shaft 702 of thefirst servo-control motor 700, it will be apparent to those skilled inthe art that the shaft 712 of the remote pit level indicator 142 willrotate an incremental amount in response to the rotational movement ofthe shaft 654 of the first recorder drive 82.

The dial-indicator 730 of the remote pit level indicator 142 will thusbe moved through a particular. incremental degree of rotation followingthe rotation of the shaft 712, and thereby provide a visual outputindication responsive to the rotational movement of the shaft 654 of thefirst recorder drive 82. More particularly, the dial-indicator 730 willthus provide a visual output indication of the level of drilling-mud inthe fluid-pits As mentioned before, the control-monitoring apparatus 10,described above, thus provides immediate, reliable, audible and visualindications of the various drilling-fluid parameters which are requiredby the operator during drilling operation. The drilling-fluid indicationapparatus 74 is particularly adapted and constructed to cooperate in adrilling-fluid circulation system to indicate the drilling-fluidlevel-change in the fluid-pits l2, and to indicate the relative flow ofdrilling-fluid in the return flow pipeline 36 in a quick, convenient andimmediately useable form. The drillingfluid indication apparatus 74 alsoprovides an indication of the volume of drilling-fluid required toinitially fill the borehole, prior to the commencement of the drillingoperation.

It should also be noted that although some of the control componentscooperating in the control-monitoring apparatus 10 have been describedin detail above as being of the electrical, pneumatic, hydraulic orfluidic type of control component, that in view of the detaileddescription above, interchangeable analogues between the basic types ofcontrol systems will be apparent to those skilled in the art.

Changes may be made in the construction and arrangement of the parts orthe elements of the various embodiments as disclosed herein withoutdeparting from the spirit and scope of the invention as defined in thefollowing claims.

12 at a remote location with respect to the position of what is claimedis:

the first recorder 76.

The remote pit level indicator is also constructed such that theoperator can easily and conveniently set the dial-indicator 730 to azero position. To zero the dial-indicator 730, the operator willinitially move the shaft 712 in a direction 728 against the biasingforce of the spring 720 to a position wherein the bevel gears 714 and716 are disengaged. In the disengaged position of the bevel gears 714and 716, the operator can then rotate the shaft 712 via the knob 726,and position the dial-indicator 730 in the proper zero position.

When the drilling pipe or a portion thereof is removed from the borehole30, the level of drillingfluid in the borehole 30 will be lowered, asdescribed before with respect to the changing of a drill-bit. In thisposition, the operator will initially zero the remote pit levelindicator 142 or, in other words, move the dial-indicator 730 to thezero position, as described above. After zeroing the dial-indicator 730,the borehole 30 is filled with drilling-fluid, in a manner as describedbefore.

The filling of the borehole 30 with drilling-fluid will cause thedial-indicator 730 to be moved or positioned on the remote pit levelindicator 142, to indicate the lowering of the level of drilling-fluidin the fluid-pits 12. When the drill-pipe is replaced in the borehole30, the drilling-fluid will be returned to the fluid-pits 12 via thereturn flow pipeline 36.

The returning of the drilling-fluid to the fluid-pits 12, should causethe dial-indicator 730 on the remote pit level indicator 142 to bereturned or again positioned substantially near the zero positionthereof. If the dialindicator 730 does not return substantially to thezero position, a possible problem is indicated to the operator such as,for example, a gas bubble in the borehole 30 or a loss of drilling-fluidin the borehole 30.

1. A control-monitoring apparatus adapted to cooperate in adrilling-fluid circulation system, comprising:

a fluid-pit for retaining a volume of drilling-fluid;

a pump connected between the fluid-pit means and the borehole pumpingdrilling-fluid from the fluidpit' means into the borehole in oneposition thereof;

a return flow pipeline connected between the borehole and the fluid-pitmeans, some of the drilling-fluid being returned to the fluid-pit meansfrom the borehole via the return flow pipeline;

level indicating means disposed in the fluid-pit and being constructedand adapted to sense the level of the drilling-fluid in the fluid-pitand to provide an output level-signal indicative of the senseddrillingfluid level;

return flow'indicator means connected to the return flow pipeline andbeing constructed and adapted to indicate the flow of drilling-fluidthrough the return flow pipeline, and to provide an" output returnflow-signal indicative of the sensed flow of drilling-fluid; and

a drilling-fluid control indication apparatus, comprising: a firstrecorder means, comprising:

a first recorder drive means constructed and adapted to receive theoutput level-signal from the level indicating means and to provide anoutput drive-signal in response thereto;

a pit indicating means constructed and adapted to receive the outputdrive-signal from the first recorder drive means and to provide anoutput level indication-signal indicative of the drilling-fluid level inthe fluid-pit; and

a second recorder means comprising:

a second recorder drive means constructed and adapted to receive theoutput return flowsignal from the return flow indicator means and toprovide an output drive-signal in response thereto; and

a return-flow indicating means constructed and adapted to receive theoutput drive-signal from the second recorder drive means and to providean output flow indication-signal indicative of the drilling-fluid flowthrough the return flow pipeline.

2. The control-monitoring apparatus of claim 1 defined further toinclude:

a pump transducer means connected to the pump and being constructed andadapted to provide an output flow-signal indicative of the volume ofdrilling-fluid being moved through the pump; and

wherein the drilling-fluid control indication apparatus is definedfurther to include:

a register means constructed and adapted to receive the outputflow-signal from the pump transducer means to provide an output volumeindication-signal indicative of the volume of drilling-fluid being movedthrough the pump.

3. The control-monitoring apparatus of claim 2 wherein thedrilling-fluid control indication apparatus is defined further toinclude:

a continuity actuator means interposed between the pump transducer meansand the register means and being constructed and adapted to receive thereturn flow-signal from the pump transducer means, the continuityactuator means having an actuated and a deactuated position, the returnflow-signal from the pump transducer means being connected to theregister means in an actuated position of the continuity actuator meansand the pump transducer means being disconnected from the register meansin a deactuated position of the continuity actuator means; and

means to actuate the continuity actuator means.

4. The control-monitoring apparatus of claim 3 wherein the continuityactuator means is further defined to include:

a relay means having an energized position and a deenergized position,the relay means being connected to the pump transducer means and theregister means to establish continuity therebetween in an energizedposition of the relay means; and

means to energize the relay means in one position thereof.

5. The control-monitoring apparatus of claim 1 defined further toinclude:

a remote pit indicating means connectedto the output drive-signal fromthe first recorder drive means and being constructed and adapted toprovide a remote output level indication-signal indicative of thedrilling-fluid level in the fluid-pits.

6. The control-monitoring apparatus of claim 1 wherein thedrilling-fluid circulation system includes more than one fluid-pit, andwherein the level indicating means is defined further to include: alevel indicating means disposed in each fluid-pit, each level indicatingmeans being connected in series to the other level indicating means toprovide an output level-signal indicative of the total drilling-fluidlevel in the fluid-pits.

7. The control-monitoring apparatus of claim 6 wherein each levelindicating means is further defined as being constructed and connectedto the other level indicating means to provide an output level-signalindicative of the total drilling-fluid level change in the fluid-pits.

8. The control-monitoring apparatus of claim 7 wherein each levelindicating means is further defined to include:

a float means disposed in the fluid-pit in contact with thedrilling-fluid, the position of the float means being changed as thedrilling-fluid level changes; and variable resistor means connected tothe float means, the resistance of the resistor means being altered bythe float means in response to a change of position of the float means,the resistor means being connected in series with the resistor means ofthe other level indicating means, the output level-signal beingresponsive to the total resistance change of the interconnected resistormeans.

9. The control-monitoring apparatus of claim 7 wherein the firstrecorder drive means is further defined to include:

a first recorder shaft rotatingly supported in the first recorder means;and

a first recorder motor having an output drive shaft drivingly connectedto the first recorder shaft, the first recorder motor being constructedand adapted to receive the output level-signal from the level indicatingmeans and to drivingly rotate the first recorder shaft in response to achange of the output level-signal.

10. The control-monitoring apparatus of claim 9 wherein the pitindicating means is further defined to include:

a dial-indicator secured to one end of the first recorder shaft, thedial-indicator movement thereby providing an instantaneous visualindication of the drilling-fluid level change in the fluidpits.

ll. The control-monitoring apparatus of claim 7 wherein the secondrecorder drive means is further to include:

a second recorder shaft rotatingly supported in the second recordermeans; and

a second recorder motor having an output drive shaft drivingly connectedto the second recorder shaft, the second recorder motor beingconstructed and adapted to receive the output flow indication signalfrom the return-flow indicating means and to drivingly rotate the secondrecorder shaft in response to a change of the output flow indicationsignal.

12. The control-monitoring apparatus of claim 11 wherein the returnflow-indicating means is further defined to include:

a dial-indicator secured to one end of the secnd recorder shaft, thedial-indicator thereby providing an instantaneous, visual indication ofthe drilling-fluid flow in the return flow line.

13. The control-monitoring apparatus of claim 1 wherein the return flowindicator means is further defined to include:

a paddle means, having opposite ends, and being disposed in a portion ofthe return flow pipeline in a position wherein a portion of the paddlemeans contacts the drilling-fluid flowing in the return dicating meansand to drivingly rotate the first recorder shaft in response to a changeof the output level-signal;

pit indicating means constructed and adapted to flow line, therebymoving the paddle means; receive the output drive-signal from the firsta paddle shaft having a portion thereof secured to recorder drive meansand to provide an outone end portion of the paddle means, the moveputlevel indication-signal indicative of the ment of the paddle means bythe drilling-fluid drilling-fluid level in the fluid-pit, including:thereby rotating the paddle shaft; a dial-indicator secured to one endof the first a return flow transducer housing having a shaftaperrecorder shaft, the dial-indicator movement ture formed through aportion thereof, the shaft thereby providing an instantaneous visualaperture sized to rotatingly receive a portion of the indication of thedrilling-fluid level change paddle shaft extending therethrough; in thefluid-pits; moisture-seal means connected to a portion of the Is chartmeans supported in the first recorder paddle shaft and to a portion ofthe return flow means; transducer housing to provideamoisture-tight seala recorder arm having a marking end, the between paddle shaft and thereturn flow transmarking end being positioned on a portion ducerhousing; and of the chart means and adapted to continuretum flowtransducer means supported in the return ously mark the portion of thechart means flow transducer housing and being connected to thereunder;and one end portion of the paddle shaft, the return acontrol cam, havingopposite ends, one end flow transducer means being constructed andportion thereof and being connected to the adapted to provide the outputreturn flow-signal in end portion of the recorder arm opposite responseto the rotational movement of the paddle the marking end thereof, andthe other opshaft. posite end of the control cam being con- 14. Acontrol-monitoring apparatus adapted to nected to first recorder shaft,the control cooperate in a drilling-fluid circulation system, comcambeing moved by the rotation of the first prising: recorder shaft,thereby positioning the a plurality of fluid-pits, each fluid-pit forretaining a 3 arki nd f the recorder arm on the volume of drillingfluid; chart means in response to the rotation of a pump connectedbetween the fluid-pit means and the drive shaft f the first recordermotor, the borehole pumping drilling-fluid from the fluidth k on the h tm an ade b the pit means into the borehole in one position arkin d therby indicatin the drillingthel'eof; fluid level change in the fluid-pitsover a a return flow pipeline connected between the r d t rmin d eriodoftirne;

borehole and the fluid-pit means, some of the second recorder means,comprising: drilling-fluid being returned to the fluid-pit means asecond recorder drive means constructed and from the borehole via thereturn flow pipeline; 40 ad t d t receive th output return flo levelindicating means disposed in each fluid-pit, i nal fr m the return flowindicator means each level indicating means being connected in seand toprovide an output drive-signal in ries to the other level indicatingmeans to provide response thereto; and an output level-signal indicativeof the sensed a return-flow indicating means constructed anddrilling-fluid level and indicative of the total adapted to receive theoutput drive-signal dr l ing-flu ve Change in the fluid P from thesecond recorder drive means and to return flow indicator means connectedto the return provide an output flow indication-signal inflow pipelineand being constructed and adapted di ative of the drilling-fluid flowthrough the to indicate the flow of drilling-fluid through the returnflow pipeline. return flow p p and to Provide an output 15. Thecontrol-monitoring apparatus of claim 14 return flow-signal indicativeof the sensed flow of wherein the first recorder means is definedfurther to drilling-fluid; and include: adrilling-fluid controlindication apparatus, comprisa high-low pit actuator means constructedand ing: adapted to receive the output drive-signal of the firstrecorder means, comprising: first recorder drive means and to provide anoutfirst recorder drive means constructe and put high-signal when theoutput drive-signal of the adapted to receive the output levelignalfirst recorder drive means reaches a preset high from the levelindicating means and to prolevel and to provide an output low-signalwhen the vide an output drive-signal in response output drive-signal ofthe first recorder means thereto, including: reaches a preset low level,thereby indicating a first recorder shaft rotatingly supported in the dt i d hi h d a d t in d l w first recorder means; and drilling-fluidlevel change in the fluid-pits. a first recorder motor having an outputdrive 16. The control-monitoring apparatus of claim 15 shaft drivinglyconnected to the first wherein the control cam includes; a high camsurface recorder shaft, the first recorder motor being constructed andadapted to receive the output level-signal from the level inand a lowcam surface formed on a portion thereof; and wherein the high-low pitactuator means is further defined to include:

1. A control-monitoring apparatus adapted to cooperate in adrilling-fluid circulation system, comprising: a fluid-pit for retaininga volume of drilling-fluid; a pump connected between the fluid-pit meansand the borehole pumping drilling-fluid from the fluid-pit means intothe borehole in one position thereof; a return flow pipeline connectedbetween the borehole and the fluid-pit means, some of the drilling-fluidbeing returned to the fluid-pit means from the borehole via the returnflow pipeline; level indicating means disposed in the fluid-pit andbeing constructed and adapted to sense the level of the drillingfluid inthe fluid-pit and to provide an output level-signal indicative of thesensed drilling-fluid level; return flow indicator means connected tothe return flow pipeline and being constructed and adapted to indicatethe flow of drilling-fluid through the return flow pipeline, and toprovide an output return flow-signal indicative of the sensed flow ofdrilling-fluid; and a drilling-fluid control indication apparatus,comprising: a first recorder means, comprising: a first recorder drivemeans constructed and adapted to receive the output level-signal fromthe level indicating means and to provide an output drive-signal inresponse thereto; a pit indicating means constructed and adapted toreceive the output drive-signal from the first recorder drive means andto provide an output level indication-signal indicative of thedrilling-fluid level in the fluid-pit; and a second recorder means,comprising: a second recorder drive means constructed and adapted toreceive the output return flow-signal from the return flow indicatormeans and to provide an output drive-signal in response thereto; and areturn-flow indicating means constructed and adapted to Receive theoutput drive-signal from the second recorder drive means and to providean output flow indication-signal indicative of the drilling-fluid flowthrough the return flow pipeline.
 2. The control-monitoring apparatus ofclaim 1 defined further to include: a pump transducer means connected tothe pump and being constructed and adapted to provide an outputflow-signal indicative of the volume of drilling-fluid being movedthrough the pump; and wherein the drilling-fluid control indicationapparatus is defined further to include: a register means constructedand adapted to receive the output flow-signal from the pump transducermeans to provide an output volume indication-signal indicative of thevolume of drilling-fluid being moved through the pump.
 3. Thecontrol-monitoring apparatus of claim 2 wherein the drilling-fluidcontrol indication apparatus is defined further to include: a continuityactuator means interposed between the pump transducer means and theregister means and being constructed and adapted to receive the returnflow-signal from the pump transducer means, the continuity actuatormeans having an actuated and a deactuated position, the returnflow-signal from the pump transducer means being connected to theregister means in an actuated position of the continuity actuator meansand the pump transducer means being disconnected from the register meansin a deactuated position of the continuity actuator means; and means toactuate the continuity actuator means.
 4. The control-monitoringapparatus of claim 3 wherein the continuity actuator means is furtherdefined to include: a relay means having an energized position and ade-energized position, the relay means being connected to the pumptransducer means and the register means to establish continuitytherebetween in an energized position of the relay means; and means toenergize the relay means in one position thereof.
 5. Thecontrol-monitoring apparatus of claim 1 defined further to include: aremote pit indicating means connected to the output drive-signal fromthe first recorder drive means and being constructed and adapted toprovide a remote output level indication-signal indicative of thedrilling-fluid level in the fluid-pits.
 6. The control-monitoringapparatus of claim 1 wherein the drilling-fluid circulation systemincludes more than one fluid-pit, and wherein the level indicating meansis defined further to include: a level indicating means disposed in eachfluid-pit, each level indicating means being connected in series to theother level indicating means to provide an output level-signalindicative of the total drilling-fluid level in the fluid-pits.
 7. Thecontrol-monitoring apparatus of claim 6 wherein each level indicatingmeans is further defined as being constructed and connected to the otherlevel indicating means to provide an output level-signal indicative ofthe total drilling-fluid level change in the fluid-pits.
 8. Thecontrol-monitoring apparatus of claim 7 wherein each level indicatingmeans is further defined to include: a float means disposed in thefluid-pit in contact with the drilling-fluid, the position of the floatmeans being changed as the drilling-fluid level changes; and a variableresistor means connected to the float means, the resistance of theresistor means being altered by the float means in response to a changeof position of the float means, the resistor means being connected inseries with the resistor means of the other level indicating means, theoutput level-signal being responsive to the total resistance change ofthe interconnected resistor means.
 9. The control-monitoring apparatusof claim 7 wherein the first recorder drive means is further defined toinclude: a first recorder shaft rotatingly supported in the firstrecorder means; and a first recorder motor having an output drive shaftdrivingly connected to the first recorder shaft, the first recorDermotor being constructed and adapted to receive the output level-signalfrom the level indicating means and to drivingly rotate the firstrecorder shaft in response to a change of the output level-signal. 10.The control-monitoring apparatus of claim 9 wherein the pit indicatingmeans is further defined to include: a dial-indicator secured to one endof the first recorder shaft, the dial-indicator movement therebyproviding an instantaneous visual indication of the drilling-fluid levelchange in the fluid-pits.
 11. The control-monitoring apparatus of claim7 wherein the second recorder drive means is further to include: asecond recorder shaft rotatingly supported in the second recorder means;and a second recorder motor having an output drive shaft drivinglyconnected to the second recorder shaft, the second recorder motor beingconstructed and adapted to receive the output flow indication signalfrom the return-flow indicating means and to drivingly rotate the secondrecorder shaft in response to a change of the output flow indicationsignal.
 12. The control-monitoring apparatus of claim 11 wherein thereturn flow-indicating means is further defined to include: adial-indicator secured to one end of the secnd recorder shaft, thedial-indicator thereby providing an instantaneous, visual indication ofthe drilling-fluid flow in the return flow line.
 13. Thecontrol-monitoring apparatus of claim 1 wherein the return flowindicator means is further defined to include: a paddle means, havingopposite ends, and being disposed in a portion of the return flowpipeline in a position wherein a portion of the paddle means contactsthe drilling-fluid flowing in the return flow line, thereby moving thepaddle means; a paddle shaft having a portion thereof secured to one endportion of the paddle means, the movement of the paddle means by thedrilling-fluid thereby rotating the paddle shaft; a return flowtransducer housing having a shaft aperture formed through a portionthereof, the shaft aperture sized to rotatingly receive a portion of thepaddle shaft extending therethrough; moisture-seal means connected to aportion of the paddle shaft and to a portion of the return flowtransducer housing to provide a moisture-tight seal between paddle shaftand the return flow transducer housing; and return flow transducer meanssupported in the return flow transducer housing and being connected toone end portion of the paddle shaft, the return flow transducer meansbeing constructed and adapted to provide the output return flow-signalin response to the rotational movement of the paddle shaft.
 14. Acontrol-monitoring apparatus adapted to cooperate in a drilling-fluidcirculation system, comprising: a plurality of fluid-pits, eachfluid-pit for retaining a volume of drilling fluid; a pump connectedbetween the fluid-pit means and the borehole pumping drilling-fluid fromthe fluid-pit means into the borehole in one position thereof; a returnflow pipeline connected between the borehole and the fluid-pit means,some of the drilling-fluid being returned to the fluid-pit means fromthe borehole via the return flow pipeline; level indicating meansdisposed in each fluid-pit, each level indicating means being connectedin series to the other level indicating means to provide an outputlevel-signal indicative of the sensed drilling-fluid level andindicative of the total drilling-fluid level change in the fluid pits;return flow indicator means connected to the return flow pipeline andbeing constructed and adapted to indicate the flow of drilling-fluidthrough the return flow pipeline, and to provide an output returnflow-signal indicative of the sensed flow of drilling-fluid; and adrilling-fluid control indication apparatus, comprising: first recordermeans, comprising: first recorder drive means constructed and adapted toreceive the output level-signal from the level indicating means and toprovide an output drive-signal in response thereto, including: firstrecorder shaft rotatingly supported in the first recorder means; and afirst recorder motor having an output drive shaft drivingly connected tothe first recorder shaft, the first recorder motor being constructed andadapted to receive the output level-signal from the level indicatingmeans and to drivingly rotate the first recorder shaft in response to achange of the output level-signal; pit indicating means constructed andadapted to receive the output drive-signal from the first recorder drivemeans and to provide an output level indication-signal indicative of thedrilling-fluid level in the fluid-pit, including: a dial-indicatorsecured to one end of the first recorder shaft, the dial-indicatormovement thereby providing an instantaneous visual indication of thedrilling-fluid level change in the fluid-pits; chart means supported inthe first recorder means; a recorder arm having a marking end, themarking end being positioned on a portion of the chart means and adaptedto continuously mark the portion of the chart means thereunder; and acontrol cam, having opposite ends, one end portion thereof and beingconnected to the end portion of the recorder arm opposite the markingend thereof, and the other opposite end of the control cam beingconnected to first recorder shaft, the control cam being moved by therotation of the first recorder shaft, thereby positioning the markingend of the recorder arm on the chart means in response to the rotationof the drive shaft of the first recorder motor, the mark on the chartmeans made by the marking end thereby indicating the drilling-fluidlevel change in the fluid-pits over a predetermined period of time;second recorder means, comprising: a second recorder drive meansconstructed and adapted to receive the output return flow-signal fromthe return flow indicator means and to provide an output drive-signal inresponse thereto; and a return-flow indicating means constructed andadapted to receive the output drive-signal from the second recorderdrive means and to provide an output flow indication-signal indicativeof the drilling-fluid flow through the return flow pipeline.
 15. Thecontrol-monitoring apparatus of claim 14 wherein the first recordermeans is defined further to include: a high-low pit actuator meansconstructed and adapted to receive the output drive-signal of the firstrecorder drive means and to provide an output high-signal when theoutput drive-signal of the first recorder drive means reaches a presethigh level and to provide an output low-signal when the outputdrive-signal of the first recorder means reaches a preset low level,thereby indicating a predetermined high and a predetermined lowdrilling-fluid level change in the fluid-pits.
 16. Thecontrol-monitoring apparatus of claim 15 wherein the control camincludes; a high cam surface and a low cam surface formed on a portionthereof; and wherein the high-low pit actuator means is further definedto include: a high-switch means constructed and adapted to provide theoutput high signal in an actuated position thereof, and being positionedand supported in the first recorder means to cooperate with the controlcam, the high-switch means being actuated by the high cam surface in oneposition of the control cam; and a low-switch means constructed andadapted to provide the output low signal in an actuated positionthereof, and being positioned and supported in the first recorder meansto cooperate with the control cam, the low-switch means being actuatedby the low cam surface in one position of the control cam.
 17. Thecontrol-monitoring apparatus of claim 16 wherein the high-low pitactuator means is further defined to include: an elongated high screwmeans turningly supported in the first recorder means; means to turn thehigh screw means; an elongated low screw means turningly suPported inthe first recorder means; and means to turn the low screw means; andwherein the high-switch means is further defined as being threadedlysupported on the high screw means, the position of the high-switch meanswith respect to the high cam surface defining the actuating preset highlevel, the position of the high-switch means with respect to the highcam surface being altered by the turning of the high screw means, theactuating preset high level being thereby adjustable; and wherein thelow-switch means is further defined as being threadedly supported on thelow screw means, the position of the low-switch means with respect tothe low cam surface defining the actuating preset low level, theposition of the low-switch means with respect to the low cam surfacebeing altered by the turning of the low screw means, the actuatingpreset low level being thereby adjustable.
 18. The control-monitoringapparatus of claim 14 wherein the high-low pit actuator means is furtherdefined to include: a high-switch means having an opened and a closedposition, the high-switch means being adapted to receive the outputdrive-signal of the first recorder drive means, the high-switch meansbeing moved to the closed position when the output drive-signal of thefirst recorder drive means reaches a preset high level, therebyproviding an output high signal in the closed position of thehigh-switch means; a low-switch means having an opened and a closedposition, the low-switch means being adapted to receive the outputdrive-signal of the first recorder drive means, the high-switch meansbeing moved to the closed position when the output drive-signal of thefirst recorder drive means reaches a preset low level, thereby providingan output low signal in the closed position of the low-switch means; ahigh level indicating means connected to the high-switch means and beingconnected thereto and adapted to provide a high level indication in theclosed position of the high-switch means; and a low level indicatingmeans connected to the low-switch means and being connected thereto andadapted to provide a low level indication in the closed position of thelow-switch means.
 19. The control-monitoring apparatus of claim 18wherein the high level indicating means and the low level indicatingmeans each are defined further to include: a lamp indicator means toprovide a visual indication; and a speaker means to provide an audibleindication.
 20. A control-monitoring apparatus adapted to cooperate in adrilling-fluid circulation system, comprising: a plurality offluid-pits, each fluid-pit for retaining a volume of drilling-fluid; apump connected between the fluid-pit means and the borehole pumpingdrilling-fluid from the fluid-pit means into the borehole in oneposition thereof; level indicating means disposed in each fluid-pit,each level indicating means being connected in series to the other levelindicating means to provide an output level-signal indicative of thesensed drilling-fluid level and indicative of the total drilling-fluidlevel change in the fluid-pits; return flow indicator means connected tothe return flow pipeline and being constructed and adapted to indicatethe flow of drilling-fluid through the return flow pipeline, and toprovide an output return flow-signal indicative of the sensed flow ofdrilling-fluid; and a drilling-fluid control indication apparatuscomprising: first recorder means, comprising: a first recorder drivemeans constructed and adapted to receive the output level-signal fromthe level indicating means and to provide an output drive-signal inresponse thereto; a pit indicating means constructed and adapted toreceive the output drive-signal from the first recorder drive means andto provide an output level indication-signal indicative of thedrilling-fluid level in the fluid-pit; and second recorder means,comprising: a second recorder drive Means constructed and adapted toreceive the output return flow-signal from the return flow indicatormeans and to provide an output drive-signal in response thereto,including: a second recorder shaft rotatingly supported in the secondrecorder means; and a second recorder motor having an output drive shaftdrivingly connected to the second recorder shaft, the second recordermotor being constructed and adapted to receive the output flowindication signal from the return-flow indicating means and to drivinglyrotate the second recorder shaft in response to a change of the outputflow indication signal; return flow indicating means constructed andadapted to receive the output drive-signal from the second recorderdrive means and to provide an output flow indication-signal indicativeof the drilling-fluid flow through the return flow pipeline, comprising:a dial-indicator secured to one end of the second recorder shaft, thedial-indicator thereby providing an instantaneous, visual indication ofthe drilling-fluid flow in the return flow line; chart means supportedin the second recorder means; a recorder arm having a marking end, themarking end being markingly positioned on a portion of the chart meansand adapted to continuously mark the portion of the chart meansthereunder; and a control cam, having opposite ends, one end portionthereof being connected to the end portion of the recorder arm oppositethe marking end thereof, and the other opposite end of the control cambeing connected to the second recorder shaft, the control cam beingmoved by the rotation of the second recorder shaft, thereby positioningthe marking end of the recorder arm on the chart means in response tothe rotation of the drive shaft of the second recorder motor, the markon the chart means made by the marking end thereby indicating the flowof drilling-fluid in the return flow pipeline over a predeterminedperiod of time.
 21. The control-monitoring apparatus of claim 20 whereinthe second recorder means is defined further to include: a high-low flowactuator means constructed and adapted to receive the outputdrive-signal from the second recorder drive means, and to provide anoutput high-signal when the output drive-signal of the second recorderdrive means reaches a preset high level and to provide an outputlow-signal when the output drive-signal of the second recorder meansreaches a preset low level, thereby indicating a predetermined highlevel and a predetermined low level of drilling-fluid flow in the returnflow pipeline.
 22. The control-monitoring apparatus of claim 21 whereinthe control cam includes; a high cam surface and a low cam surfaceformed on a portion thereof; and wherein the high-low flow actuatormeans is defined further to include: a high-switch means constructed andadapted to provide the output high signal in an actuated positionthereof and being positioned and supported in the second recorder meansto cooperate with the control cam, the high-switch means being actuatedby the high cam surface, in one position of the control cam; and alow-switch means constructed and adapted to provide the output lowsignal in an actuated position thereof, and being positioned in thesecond recorder means to cooperate with the control cam, the low-switchmeans being actuated by the low cam surface in one position of thecontrol cam.
 23. The control-monitoring apparatus of claim 22 whereinthe high-low flow actuator means is defined further to include: anelongated high screw means turningly supported in the second recordermeans; means to turn the high screw means; an elongated low screw meansturningly supported in the second recorder means; and means to turn thelow screw means; and wherein the high-switch means is further defined asbeing threadedly supported on the high screw means, the position of thehigh screw means with respect to the high cam surface defining theactuating preset High level, the position of the high-switch means withrespect to the high cam surface being altered by the turning of the highscrew means, the actuating preset high level being thereby adjustable;and wherein the low-switch means is further defined as being threadedlysupported on the low screw means, the position of the low-switch meanswith respect to the low cam surface defining the actuating preset lowlevel, the position of the low-switch means with respect to the low camsurface being altered by the turning of the low screw means, theactuating preset low level being thereby adjustable.
 24. Thecontrol-monitoring apparatus of claim 20 wherein the high-low flowactuator means is further defined to include: a high-switch means havingan opened and a closed position, the high-switch means being adapted toreceive the output drive-signal of the second recorder drive means, thehigh-switch means being moved to the closed position when the outputdrive-signal of the second recorder drive means reaches a preset highlevel, thereby providing an output high signal in the closed position ofthe high-switch means; a low-switch means having an opened and a closedposition, the low-switch means being adapted to receive the outputdrive-signal of the second recorder drive means, the high-switch meansbeing moved to the closed position when the output drive-signal of thesecond recorder drive means reaches a preset low level, therebyproviding an output low signal in the closed position of the low-switchmeans; a high flow indicating means connected to the high-switch meansand being connected thereto and adapted to provide a high flowindication in the closed position of the high-switch means; and a lowflow indicating means connected to the low-switch means and beingconnected thereto and adapted to provide a low flow indication in theclosed position of the low-switch means.
 25. The control-monitoringapparatus of claim 24 wherein the high flow indicating means and the lowflow indicating means each are defined further to include: a lampindicator means to provide a visual indication; and a speaker to providean audible indication.
 26. The control-monitoring apparatus of claim 24is defined further to include: a flow switch means having an opened anda closed position connected to the low-switch means, the flow switchmeans being in electrical continuity with the low flow indicating meansin the closed position of the flow switch means and in the closedposition of the low-switch means; and means connected to the flow switchmeans, and being adapted to receive the output flow indication signalfrom the return flow indicating means and to close the flow switch meanswhen the output flow indication signal indicates drilling-fluid flow inthe return flow pipeline thereby establishing electrical continuitybetween the low flow indicating means and the flow switch means via thelow-switch means, in a closed position of the low-switch means.
 27. Acontrol-monitoring apparatus adapted to cooperate in a drilling-fluidcirculation system, comprising: a plurality of fluid-pits, eachfluid-pit for retaining a volume of drilling fluid; a pump connectedbetween the fluid-pit means and the borehole pumping drilling-fluid fromthe fluid-pit means into the borehole in one position thereof; a returnflow pipeline connected between the borehole and the fluid-pit means,some of the drilling-fluid being returned to the fluid-pit means fromthe borehole via the return flow pipeline; level indicating meansdisposed in each fluid-pit, each level indicating means being connectedin series to the other level indicating means to provide an outputlevel-signal indicative of the sensed drilling-fluid level andindicative of the total drilling-fluid level change in the fluid-pits;return flow indicator means connected to the return flow pipeline andbeing constructed and adapted to indicate the flow of drilling-fluidthrough the return flow pipeline, and to provide an output returnflow-signal indicative of the sensed flow of drilling-fluid; and adrilling-fluid control indication apparatus, comprising: a firstrecorder means, comprising: first recorder drive means constructed andadapted to receive the output level-signal from the level indicatingmeans and to provide an output drive-signal in response thereto,including: a first recorder shaft rotatingly supported in the firstrecorder means; and a first recorder motor having an output drive shaftdrivingly connected to the first recorder shaft, the first recordermotor being constructed and adapted to receive the output level-signalfrom the level indicating means and to drivingly rotate the firstrecorder shaft in response to a change of the output level-signal; a pitindicating means constructed and adapted to receive the outputdrive-signal from the first recorder drive means and to provide anoutput level indication-signal indicative of the drilling-fluid level inthe fluid-pit; a first servo-control means having an output servo shaftconnected to the first recorder shaft, the rotation of the servo shaftthereby being responsive to the rotation of the first recorder shaft; asecond recorder means, comprising: second recorder drive meansconstructed and adapted to receive the output return flow-signal fromthe return flow indicator means and to provide an output drive-signal inresponse thereto; and a return-flow indicating means constructed andadapted to receive the output drive-signal from the second recorderdrive means and to provide an output flow indication-signal indicativeof the drilling-fluid flow through the return flow pipeline; a remotepit indicating means, comprising: a shaft rotatingly supported in aportion of the remote pit level indicating means; and a secondservo-control means having an output servo shaft drivingly connected toa portion of the shaft in the remote pit indicating means, the secondservo-control means being connected to the first servo-control means sothat the second servo means drivingly rotates the shaft in the remotepit indicating means in response to the rotation of the servo shaft ofthe first servo-control means.
 28. The control-monitoring apparatus ofclaim 27 wherein the remote pit indicating means is further defined toinclude: a gear means connected to the shaft of the second servo-controlmeans and to the shaft in the remote pit indicating means, the gearmeans thereby providing the driving connection therebetween, the gearmeans being sized to amplify the rotational movement of the servo shaftof the second servo-control means, the incremental degree of rotation ofthe shaft in the remote pit indicating means being thereby greater thanthe rotation of the shaft of the first recorder means.
 29. Thecontrol-monitoring apparatus of claim 28 wherein the remote pitindicating means is further defined to include: a biasing meanssupported in the remote pit indicating means, a portion of the biasingmeans being in biasing engagement with the shaft in the remote pitindicating means, the biasing means being sized and disposed tobiasingly maintain the gearing interconnection between the shaft of thesecond servo-control means and the shaft in the remote pit indicatingmeans; and wherein the shaft in the remote pit indicating means isfurther defined as being slidably disposed therein, the gearinginterconnection between the shaft of the second servo-control means theshaft of the remote pit indicating means being disconnected by thesliding of the shaft in the remote pit indicating means a predetermineddistance against the biasing force of the biasing means, the shaft inthe remote pit indicating means being thereby rotatable to apredetermined position.
 30. The control-monitoring apparatus of claim 29wherein the remote pit indicating means is further defined to include: adial-indicator secured to one end of the shaft in the remote return flowindicating means, the dial-indicator thereby providing an instantaneous,visual indication of the drilling-fluid level in the fluid-bits at aremote position with respect to the first recorder means.
 31. Acontrol-monitoring apparatus adapted to cooperate in a drilling-fluidcirculation sytem, comprising: a fluid-pit for retaining a volume ofdrilling-fluid; a pump connected between the fluid-pit means and theborehole pumping drilling-fluid from the fluid-pit means into theborehole in one position thereof; a return flow pipeline connectedbetween the borehole and the fluid-pit means, some of the drilling-fluidbeing returned to the fluid-pit means from the borehole via the returnflow pipeline; level indicating means disposed in the fluid-pit andbeing constructed and adapted to sense the level of the drilling-fluidin the fluid-pit and to provide an output level-signal indicative of thesensed drilling-fluid level; return flow indicator means connected tothe return flow pipeline and being constructed and adapted to indicatethe flow of drilling-fluid through the return flow pipeline, and toprovide an output return flow-signal indicative of the sensed flow ofdrilling-fluid, comprising: a paddle means, having opposite ends, andbeing disposed in a portion of the return flow pipeline in a positionwherein a portion of the paddle means contacts the drilling-fluidflowing in the return flow line, thereby moving the paddle means; apaddle shaft having a portion thereof secured to one end portion of thepaddle means, the movement of the paddle means by the drilling-fluidthereby rotating the paddle shaft; a return flow transducer housinghaving a shaft aperture formed through a portion thereof, the shaftaperture sized to rotatingly receive a portion of the paddle shaftextending therethrough; moisture-seal means connected to a portion ofthe paddle shaft an to a portion of the return flow transducer housingto provide a moisture-tight seal between paddle shaft and the returnflow transducer housing, comprising: a hollow stationary member, havingopposite ends and an outer periphery, one end of the stationary memberbeing sealingly secured to the return flow transducer housing, thehollow portion of the stationary member encompassing the shaft apertureand a portion of the paddle shaft, the paddle shaft being freelyrotatable therein; a lip portion formed on the end of the stationarymember opposite the end thereof secured to the return flow transducerhousing, the lip portion extending a distance radially from thestationary member about the outer periphery thereof; and a hollowrotating member, having opposite ends and an inner and an outerperiphery, one end of the rotating member being secured to a portion ofthe paddle shaft, the end of the rotating member, opposite the endthereof secured to the paddle shaft, extending a distance axially overthe lip portion of the stationary member; return flow transducer meanssupported in the return flow transducer housing and being connected toone end portion of the paddle shaft, the return flow transducer meansbeing constructed and adapted to provide the output return flow-signalin response to the rotational movement of the paddle shaft; and adrilling-fluid control indication apparatus comprising: a first recordermeans, comprising: a first recorder drive means constructed and adaptedto receive the output level-signal from the level indicating means andto provide an output drive-signal in response thereto; a pit indicatingmeans constructed and adapted to receive the output drive-signal fromthe first recorder drive means and to provide an output levelindication-signal indicative of the drilling-fluid level in thefluid-pit; and a second recorder means, comprising: a second recorderdrive means constructed and adapted to receive the output returNflow-signal from the return flow indicator means and to provide anoutput drive-signal in response thereto; and a return-flow indicatingmeans constructed and adapted to receive the output drive-signal fromthe second recorder drive means and to provide an output flowindication-signal indicative of the drilling-fluid flow through thereturn flow pipeline.
 32. A control-monitoring apparatus adapted tocooperate in a drilling-fluid circulating system, comprising: afluid-pit for retaining a volume of drilling-fluid; a pump connectedbetween the fluid-pit means and the borehole pumping drilling-fluid fromthe fluid-pit means into the borehole in one position thereof; a returnflow pipeline connected between the borehole and the fluid-pit means,some of the drilling-fluid being returned to the fluid-pit means fromthe borehole via the return flow pipeline; level indicating meansdisposed in the fluid-pit and being constructed and adapted to sense thelevel of the drilling-fluid in the fluid-pit and to provide an outputlevel-signal indicative of the sensed drilling-fluid level; return flowindicator means connected to the return flow pipeline and beingconstructed and adapted to indicate the flow of drilling-fluid throughthe return flow pipeline, and to provide an output return flow-signalindicative of the sensed flow of drilling-fluid; and a drilling-fluidcontrol indication apparatus, comprising: a first recorder means,comprising: a first recorder drive means constructed and adapted toreceive the output level-signal from the level indicating means and toprovide an output drive-signal in response thereto; a pit indicatingmeans constructed and adapted to receive the output drive-signal fromthe first recorder drive means and to provide an output levelindication-signal indication of the drilling-fluid level in thefluid-pit; and a second recorder means, comprising: a second recorderdrive means constructed and adapted to receive the output returnflow-signal from the return flow indicator means and to provide anoutput drive-signal in response thereto; and a return-flow indicatingmeans constructed and adapted to receive the output drive-signal fromthe second recorder drive means and to provide an output flowindication-signal indicative of the drilling-fluid flow through thereturn flow pipeline; a pump transducer means connected to the pump andbeing constructed and adapted to provide an output flow-signalindicative of the volume of drilling-fluid being moved through the pump;a register means constructed and adapted to receive the outputflow-signal from the pump transducer means to provide an output volumeindication-signal indicative of the volume of drilling-fluid being movedthrough the pump; a continuity actuator means interposed between thepump transducer means and the register means and being constructed andadapted to receive the return flow-signal from the pump transducermeans, the continuity actuator means having an actuated and a deactuatedposition, the return flow-signal from the pump transducer means beingconnected to the register means in an actuated position of thecontinuity actuator means and the pump transducer means beingdisconnected from the register means in a deactuated position of thecontinuity actuator means, comprising: a relay means having an energizedposition and a de-energized position, the relay means being connected tothe pump transducer means and the register means to establish continuitytherebetween in an energized positon of th realy mans, comprising: apower supply means connected to the relay means to provide energizingpower therefor when connected thereto; a momentary switch means, havinga deactuated and an actuated position, the momentary switch means beinginterposed between the power supply means and relay means, the momentaryswitch means connecting the and relay means, the momentary switch meansconNecting the power supply means to the relay means in an actuatedposition thereof and disconnecting the power supply means from the relaymeans in a deactuated position thereof; a holding relay means, having anenergized position and a deenergized position, the holding relay meansbeing connected to the power supply means and to the relay means, in ade-energized position thereof, the relay means being constructed toprovide continuity between the relay means and the power supply meansvia the holding relay means, in an energized position of the relay meansand in a de-energized position of the holding relay means, the relaymeans thereby cooperating with the holding relay means to maintain therelay means energized after the momentary switch means is moved from anactuated to a deactuated position; and means to energize the relay meansin one position thereof.
 33. The control-monitoring apparatus of claim32 wherein the means to de-energize the holding relay means is furtherdefined to include: a power supply means connected to the holding relaymeans to provide energizing power therefor when connected thereto; azero flow switch means, having an opened and a closed position, andbeing interposed between the holding relay means and the power supplymeans, the zero flow switch means connecting the power supply means tothe holding relay means in the closed position thereof, anddisconnecting the power supply means from the holding relay means in anopened position thereof; and means connected to the zero flow switchmeans, and being adapted to receive the output flow indication signalfrom the return flow indicating means and to close the zero flow switchmeans when the output flow indication signal indicates drilling-fluidflow in the return flow pipeline.